Merge branch 'pks-tx-voting-phases' into 'master'

proto: Introduce transactional voting phases

See merge request gitlab-org/gitaly!4180

33 files changed, 487 insertions, 299 deletions

diff --git a/internal/git/housekeeping/housekeeping_test.go b/internal/git/housekeeping/housekeeping_test.go
index c70143080..2daae8b96 100644
--- a/internal/git/housekeeping/housekeeping_test.go
+++ b/internal/git/housekeeping/housekeeping_test.go
@@ -2,7 +2,6 @@ package housekeeping
 
 import (
 	"bytes"
-	"context"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -20,7 +19,6 @@ import (
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testcfg"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/txinfo"
-	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/voting"
 	"google.golang.org/grpc/peer"
 )
 
@@ -706,13 +704,7 @@ func TestPerform_UnsetConfiguration_transactional(t *testing.T) {
 
 	gittest.Exec(t, cfg, "-C", repoPath, "config", "http.some.extraHeader", "value")
 
-	votes := 0
-	txManager := &transaction.MockManager{
-		VoteFn: func(context.Context, txinfo.Transaction, voting.Vote) error {
-			votes++
-			return nil
-		},
-	}
+	txManager := transaction.NewTrackingManager()
 
 	ctx, err := txinfo.InjectTransaction(ctx, 1, "node", true)
 	require.NoError(t, err)
@@ -721,8 +713,7 @@ func TestPerform_UnsetConfiguration_transactional(t *testing.T) {
 	})
 
 	require.NoError(t, Perform(ctx, repo, txManager))
-
-	require.Equal(t, 2, votes)
+	require.Equal(t, 2, len(txManager.Votes()))
 
 	configKeys := gittest.Exec(t, cfg, "-C", repoPath, "config", "--list", "--local", "--name-only")
 
diff --git a/internal/git/localrepo/config_test.go b/internal/git/localrepo/config_test.go
index e0d188cf4..2a31977a7 100644
--- a/internal/git/localrepo/config_test.go
+++ b/internal/git/localrepo/config_test.go
@@ -1,7 +1,6 @@
 package localrepo
 
 import (
-	"context"
 	"fmt"
 	"path/filepath"
 	"runtime"
@@ -18,7 +17,6 @@ import (
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testcfg"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/txinfo"
-	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/voting"
 	"google.golang.org/grpc/peer"
 )
 
@@ -121,17 +119,12 @@ func TestRepo_SetConfig(t *testing.T) {
 		ctx, err := txinfo.InjectTransaction(ctx, 1, "node", true)
 		ctx = peer.NewContext(ctx, backchannelPeer)
 
-		votes := 0
+		txManager := transaction.NewTrackingManager()
 
 		require.NoError(t, err)
-		require.NoError(t, repo.SetConfig(ctx, "some.key", "value", &transaction.MockManager{
-			VoteFn: func(context.Context, txinfo.Transaction, voting.Vote) error {
-				votes++
-				return nil
-			},
-		}))
+		require.NoError(t, repo.SetConfig(ctx, "some.key", "value", txManager))
 
-		require.Equal(t, 2, votes)
+		require.Equal(t, 2, len(txManager.Votes()))
 	})
 }
 
@@ -262,16 +255,11 @@ func TestRepo_UnsetMatchingConfig(t *testing.T) {
 		ctx, err := txinfo.InjectTransaction(ctx, 1, "node", true)
 		ctx = peer.NewContext(ctx, backchannelPeer)
 
-		votes := 0
+		txManager := transaction.NewTrackingManager()
 
 		require.NoError(t, err)
-		require.NoError(t, repo.UnsetMatchingConfig(ctx, "some.key", &transaction.MockManager{
-			VoteFn: func(context.Context, txinfo.Transaction, voting.Vote) error {
-				votes++
-				return nil
-			},
-		}))
+		require.NoError(t, repo.UnsetMatchingConfig(ctx, "some.key", txManager))
 
-		require.Equal(t, 2, votes)
+		require.Equal(t, 2, len(txManager.Votes()))
 	})
 }
diff --git a/internal/git/objectpool/link_test.go b/internal/git/objectpool/link_test.go
index 3a45adb37..c960f48db 100644
--- a/internal/git/objectpool/link_test.go
+++ b/internal/git/objectpool/link_test.go
@@ -1,7 +1,6 @@
 package objectpool
 
 import (
-	"context"
 	"os"
 	"path/filepath"
 	"strings"
@@ -13,7 +12,6 @@ import (
 	"gitlab.com/gitlab-org/gitaly/v14/internal/gitaly/transaction"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/txinfo"
-	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/voting"
 	"google.golang.org/grpc/peer"
 )
 
@@ -54,13 +52,8 @@ func TestLink_transactional(t *testing.T) {
 	pool, poolMember := setupObjectPool(t)
 	require.NoError(t, pool.Create(ctx, poolMember))
 
-	votes := 0
-	pool.txManager = &transaction.MockManager{
-		VoteFn: func(context.Context, txinfo.Transaction, voting.Vote) error {
-			votes++
-			return nil
-		},
-	}
+	txManager := transaction.NewTrackingManager()
+	pool.txManager = txManager
 
 	alternatesPath, err := pool.locator.InfoAlternatesPath(poolMember)
 	require.NoError(t, err)
@@ -74,7 +67,7 @@ func TestLink_transactional(t *testing.T) {
 
 	require.NoError(t, pool.Link(ctx, poolMember))
 
-	require.Equal(t, 2, votes)
+	require.Equal(t, 2, len(txManager.Votes()))
 }
 
 func TestLinkRemoveBitmap(t *testing.T) {
diff --git a/internal/gitaly/hook/referencetransaction.go b/internal/gitaly/hook/referencetransaction.go
index f391876e0..bba8eaabe 100644
--- a/internal/gitaly/hook/referencetransaction.go
+++ b/internal/gitaly/hook/referencetransaction.go
@@ -9,6 +9,7 @@ import (
 	"io"
 
 	"gitlab.com/gitlab-org/gitaly/v14/internal/git"
+	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/voting"
 )
 
 // forceDeletionPrefix is the prefix of a queued reference transaction which deletes a
@@ -27,13 +28,19 @@ func (m *GitLabHookManager) ReferenceTransactionHook(ctx context.Context, state
 		return fmt.Errorf("reading stdin from request: %w", err)
 	}
 
+	var phase voting.Phase
+	switch state {
 	// We're voting in prepared state as this is the only stage in Git's reference transaction
-	// which allows us to abort the transaction. We're also voting in committed state to tell
-	// Praefect we've actually persisted the changes. This is necessary as some RPCs fail return
-	// errors in the response body rather than as an error code. Praefect can't tell if these RPCs
-	// have failed. Voting on committed ensure Praefect sees either a missing vote or that the RPC did
-	// commit the changes.
-	if state != ReferenceTransactionPrepared && state != ReferenceTransactionCommitted {
+	// which allows us to abort the transaction.
+	case ReferenceTransactionPrepared:
+		phase = voting.Prepared
+	// We're also voting in committed state to tell Praefect we've actually persisted the
+	// changes. This is necessary as some RPCs fail return errors in the response body rather
+	// than as an error code. Praefect can't tell if these RPCs have failed. Voting on committed
+	// ensure Praefect sees either a missing vote or that the RPC did commit the changes.
+	case ReferenceTransactionCommitted:
+		phase = voting.Committed
+	default:
 		return nil
 	}
 
@@ -61,7 +68,7 @@ func (m *GitLabHookManager) ReferenceTransactionHook(ctx context.Context, state
 
 	hash := sha1.Sum(changes)
 
-	if err := m.voteOnTransaction(ctx, hash, payload); err != nil {
+	if err := m.voteOnTransaction(ctx, hash, phase, payload); err != nil {
 		return fmt.Errorf("error voting on transaction: %w", err)
 	}
 
diff --git a/internal/gitaly/hook/transactions.go b/internal/gitaly/hook/transactions.go
index 78cd82c4c..33097b551 100644
--- a/internal/gitaly/hook/transactions.go
+++ b/internal/gitaly/hook/transactions.go
@@ -32,9 +32,14 @@ func (m *GitLabHookManager) runWithTransaction(ctx context.Context, payload git.
 	return nil
 }
 
-func (m *GitLabHookManager) voteOnTransaction(ctx context.Context, vote voting.Vote, payload git.HooksPayload) error {
+func (m *GitLabHookManager) voteOnTransaction(
+	ctx context.Context,
+	vote voting.Vote,
+	phase voting.Phase,
+	payload git.HooksPayload,
+) error {
 	return m.runWithTransaction(ctx, payload, func(ctx context.Context, tx txinfo.Transaction) error {
-		return m.txManager.Vote(ctx, tx, vote)
+		return m.txManager.Vote(ctx, tx, vote, phase)
 	})
 }
 
diff --git a/internal/gitaly/hook/transactions_test.go b/internal/gitaly/hook/transactions_test.go
index 0f1759b95..de9f7d7cb 100644
--- a/internal/gitaly/hook/transactions_test.go
+++ b/internal/gitaly/hook/transactions_test.go
@@ -124,7 +124,7 @@ func TestHookManager_contextCancellationCancelsVote(t *testing.T) {
 	cfg, repo, _ := testcfg.BuildWithRepo(t)
 
 	mockTxMgr := transaction.MockManager{
-		VoteFn: func(ctx context.Context, tx txinfo.Transaction, vote voting.Vote) error {
+		VoteFn: func(ctx context.Context, _ txinfo.Transaction, _ voting.Vote, _ voting.Phase) error {
 			<-ctx.Done()
 			return fmt.Errorf("mock error: %s", ctx.Err())
 		},
diff --git a/internal/gitaly/service/operations/apply_patch_test.go b/internal/gitaly/service/operations/apply_patch_test.go
index 89b50f4f0..b0676804d 100644
--- a/internal/gitaly/service/operations/apply_patch_test.go
+++ b/internal/gitaly/service/operations/apply_patch_test.go
@@ -1,12 +1,10 @@
 package operations
 
 import (
-	"context"
 	"fmt"
 	"io"
 	"os"
 	"strings"
-	"sync/atomic"
 	"testing"
 	"testing/iotest"
 	"time"
@@ -26,7 +24,6 @@ import (
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testcfg"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testserver"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/txinfo"
-	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/voting"
 	"gitlab.com/gitlab-org/gitaly/v14/proto/go/gitalypb"
 	"gitlab.com/gitlab-org/gitaly/v14/streamio"
 	"google.golang.org/grpc/codes"
@@ -621,16 +618,7 @@ func TestUserApplyPatchTransactional(t *testing.T) {
 	ctx, cancel := testhelper.Context()
 	defer cancel()
 
-	var votes int32
-	txManager := &transaction.MockManager{
-		VoteFn: func(context.Context, txinfo.Transaction, voting.Vote) error {
-			// We can see a race here between adding the worktree and changing its
-			// config and updating refs via the reference-transaction hook. Given that
-			// both come in via different threads, Go perceives it as a potential race.
-			atomic.AddInt32(&votes, 1)
-			return nil
-		},
-	}
+	txManager := transaction.NewTrackingManager()
 
 	ctx, cfg, repoProto, repoPath, client := setupOperationsService(t, ctx, testserver.WithTransactionManager(txManager))
 
@@ -665,7 +653,7 @@ func TestUserApplyPatchTransactional(t *testing.T) {
 
 	require.True(t, response.BranchUpdate.BranchCreated)
 
-	require.Equal(t, int32(14), votes)
+	require.Equal(t, 14, len(txManager.Votes()))
 
 	splitIndex := gittest.Exec(t, cfg, "-C", repoPath, "config", "core.splitIndex")
 	require.Equal(t, "false", text.ChompBytes(splitIndex))
diff --git a/internal/gitaly/service/operations/rebase_test.go b/internal/gitaly/service/operations/rebase_test.go
index 555c7048c..5c05880b3 100644
--- a/internal/gitaly/service/operations/rebase_test.go
+++ b/internal/gitaly/service/operations/rebase_test.go
@@ -1,7 +1,6 @@
 package operations
 
 import (
-	"context"
 	"fmt"
 	"io"
 	"strings"
@@ -18,7 +17,6 @@ import (
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testserver"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/txinfo"
-	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/voting"
 	"gitlab.com/gitlab-org/gitaly/v14/proto/go/gitalypb"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/protobuf/proto"
@@ -93,13 +91,7 @@ func TestUserRebaseConfirmableTransaction(t *testing.T) {
 	ctx, cancel := testhelper.Context()
 	defer cancel()
 
-	var voteCount int
-	txManager := &transaction.MockManager{
-		VoteFn: func(context.Context, txinfo.Transaction, voting.Vote) error {
-			voteCount++
-			return nil
-		},
-	}
+	txManager := transaction.NewTrackingManager()
 
 	ctx, cfg, repoProto, repoPath, client := setupOperationsService(
 		t, ctx,
@@ -141,7 +133,7 @@ func TestUserRebaseConfirmableTransaction(t *testing.T) {
 		t.Run(tc.desc, func(t *testing.T) {
 			preReceiveHookOutputPath := gittest.WriteEnvToCustomHook(t, repoPath, "pre-receive")
 
-			voteCount = 0
+			txManager.Reset()
 
 			ctx := ctx
 			if tc.withTransaction {
@@ -173,7 +165,7 @@ func TestUserRebaseConfirmableTransaction(t *testing.T) {
 			require.Nil(t, response)
 			require.Equal(t, io.EOF, err)
 
-			require.Equal(t, tc.expectedVotes, voteCount)
+			require.Equal(t, tc.expectedVotes, len(txManager.Votes()))
 			if tc.expectPreReceiveHook {
 				require.FileExists(t, preReceiveHookOutputPath)
 			} else {
diff --git a/internal/gitaly/service/ref/delete_refs.go b/internal/gitaly/service/ref/delete_refs.go
index 26e6d2929..222432ed0 100644
--- a/internal/gitaly/service/ref/delete_refs.go
+++ b/internal/gitaly/service/ref/delete_refs.go
@@ -60,11 +60,18 @@ func (s *server) DeleteRefs(ctx context.Context, in *gitalypb.DeleteRefsRequest)
 		return nil, helper.ErrInternalf("could not compute vote: %v", err)
 	}
 
+	// We don't use proper two-phase voting when the feature flag is disabled, so we use
+	// `UnknownPhase` in that case.
+	preparedPhase := voting.UnknownPhase
+	if featureflag.TxTwoPhaseDeleteRefs.IsEnabled(ctx) {
+		preparedPhase = voting.Prepared
+	}
+
 	// All deletes we're doing in this RPC are force deletions. Because we're required to filter
 	// out transactions which only consist of force deletions, we never do any voting via the
 	// reference-transaction hook here. Instead, we need to resort to a manual vote which is
 	// simply the concatenation of all reference we're about to delete.
-	if err := transaction.VoteOnContext(ctx, s.txManager, vote); err != nil {
+	if err := transaction.VoteOnContext(ctx, s.txManager, vote, preparedPhase); err != nil {
 		return nil, helper.ErrInternalf("preparatory vote: %w", err)
 	}
 
@@ -77,7 +84,7 @@ func (s *server) DeleteRefs(ctx context.Context, in *gitalypb.DeleteRefsRequest)
 	}
 
 	if featureflag.TxTwoPhaseDeleteRefs.IsEnabled(ctx) {
-		if err := transaction.VoteOnContext(ctx, s.txManager, vote); err != nil {
+		if err := transaction.VoteOnContext(ctx, s.txManager, vote, voting.Committed); err != nil {
 			return nil, helper.ErrInternalf("committing vote: %w", err)
 		}
 	}
diff --git a/internal/gitaly/service/ref/delete_refs_test.go b/internal/gitaly/service/ref/delete_refs_test.go
index b52c3f74c..b508e4308 100644
--- a/internal/gitaly/service/ref/delete_refs_test.go
+++ b/internal/gitaly/service/ref/delete_refs_test.go
@@ -17,7 +17,6 @@ import (
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testcfg"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testserver"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/txinfo"
-	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/voting"
 	"gitlab.com/gitlab-org/gitaly/v14/proto/go/gitalypb"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
@@ -92,13 +91,7 @@ func testDeleteRefsTransaction(t *testing.T, ctx context.Context) {
 
 	testcfg.BuildGitalyHooks(t, cfg)
 
-	var votes int
-	txManager := &transaction.MockManager{
-		VoteFn: func(context.Context, txinfo.Transaction, voting.Vote) error {
-			votes++
-			return nil
-		},
-	}
+	txManager := transaction.NewTrackingManager()
 
 	addr := testserver.RunGitalyServer(t, cfg, nil, func(srv *grpc.Server, deps *service.Dependencies) {
 		gitalypb.RegisterRefServiceServer(srv, NewServer(
@@ -139,7 +132,7 @@ func testDeleteRefsTransaction(t *testing.T, ctx context.Context) {
 		},
 	} {
 		t.Run(tc.desc, func(t *testing.T) {
-			votes = 0
+			txManager.Reset()
 
 			repo, _ := gittest.CloneRepo(t, cfg, cfg.Storages[0])
 			tc.request.Repository = repo
@@ -153,7 +146,7 @@ func testDeleteRefsTransaction(t *testing.T, ctx context.Context) {
 				expectedVotes *= 2
 			}
 
-			require.Equal(t, expectedVotes, votes)
+			require.Equal(t, expectedVotes, len(txManager.Votes()))
 		})
 	}
 }
diff --git a/internal/gitaly/service/repository/apply_gitattributes.go b/internal/gitaly/service/repository/apply_gitattributes.go
index 82a08d1a1..8f188183a 100644
--- a/internal/gitaly/service/repository/apply_gitattributes.go
+++ b/internal/gitaly/service/repository/apply_gitattributes.go
@@ -66,7 +66,7 @@ func (s *server) applyGitattributes(ctx context.Context, repo *localrepo.Repo, o
 
 			// We use the zero OID as placeholder to vote on removal of the
 			// gitattributes file.
-			if err := s.vote(ctx, git.ZeroOID); err != nil {
+			if err := s.vote(ctx, git.ZeroOID, voting.Prepared); err != nil {
 				return fmt.Errorf("preimage vote: %w", err)
 			}
 
@@ -74,7 +74,7 @@ func (s *server) applyGitattributes(ctx context.Context, repo *localrepo.Repo, o
 				return err
 			}
 
-			if err := s.vote(ctx, git.ZeroOID); err != nil {
+			if err := s.vote(ctx, git.ZeroOID, voting.Committed); err != nil {
 				return fmt.Errorf("postimage vote: %w", err)
 			}
 
@@ -83,7 +83,7 @@ func (s *server) applyGitattributes(ctx context.Context, repo *localrepo.Repo, o
 
 		// If there is no gitattributes file, we simply use the ZeroOID
 		// as a placeholder to vote on the removal.
-		if err := s.vote(ctx, git.ZeroOID); err != nil {
+		if err := s.vote(ctx, git.ZeroOID, voting.UnknownPhase); err != nil {
 			return fmt.Errorf("could not remove gitattributes: %w", err)
 		}
 
@@ -114,7 +114,7 @@ func (s *server) applyGitattributes(ctx context.Context, repo *localrepo.Repo, o
 	return nil
 }
 
-func (s *server) vote(ctx context.Context, oid git.ObjectID) error {
+func (s *server) vote(ctx context.Context, oid git.ObjectID, phase voting.Phase) error {
 	tx, err := txinfo.TransactionFromContext(ctx)
 	if errors.Is(err, txinfo.ErrTransactionNotFound) {
 		return nil
@@ -130,7 +130,7 @@ func (s *server) vote(ctx context.Context, oid git.ObjectID) error {
 		return fmt.Errorf("cannot convert OID to vote: %w", err)
 	}
 
-	if err := s.txManager.Vote(ctx, tx, vote); err != nil {
+	if err := s.txManager.Vote(ctx, tx, vote, phase); err != nil {
 		return fmt.Errorf("vote failed: %w", err)
 	}
 
diff --git a/internal/gitaly/service/repository/create_repository.go b/internal/gitaly/service/repository/create_repository.go
index 334d8b79b..7d3243eb9 100644
--- a/internal/gitaly/service/repository/create_repository.go
+++ b/internal/gitaly/service/repository/create_repository.go
@@ -84,7 +84,7 @@ func (s *server) CreateRepository(ctx context.Context, req *gitalypb.CreateRepos
 			return err
 		}
 
-		if err := s.txManager.Vote(ctx, tx, vote); err != nil {
+		if err := s.txManager.Vote(ctx, tx, vote, voting.UnknownPhase); err != nil {
 			return fmt.Errorf("casting vote: %w", err)
 		}
 
diff --git a/internal/gitaly/service/repository/create_repository_from_bundle_test.go b/internal/gitaly/service/repository/create_repository_from_bundle_test.go
index 90ab876d9..668b135f5 100644
--- a/internal/gitaly/service/repository/create_repository_from_bundle_test.go
+++ b/internal/gitaly/service/repository/create_repository_from_bundle_test.go
@@ -104,16 +104,9 @@ func TestCreateRepositoryFromBundle_transactional(t *testing.T) {
 }
 
 func testCreateRepositoryFromBundleTransactional(t *testing.T, ctx context.Context) {
-	var votes []voting.Vote
-	txManager := &transaction.MockManager{
-		VoteFn: func(ctx context.Context, tx txinfo.Transaction, vote voting.Vote) error {
-			votes = append(votes, vote)
-			return nil
-		},
-	}
+	txManager := transaction.NewTrackingManager()
 
-	cfg, repoProto, repoPath, client := setupRepositoryService(t,
-		testserver.WithTransactionManager(txManager))
+	cfg, repoProto, repoPath, client := setupRepositoryService(t, testserver.WithTransactionManager(txManager))
 
 	masterOID := text.ChompBytes(gittest.Exec(t, cfg, "-C", repoPath, "rev-parse", "refs/heads/master"))
 	featureOID := text.ChompBytes(gittest.Exec(t, cfg, "-C", repoPath, "rev-parse", "refs/heads/feature"))
@@ -155,50 +148,43 @@ func testCreateRepositoryFromBundleTransactional(t *testing.T, ctx context.Conte
 	require.NoError(t, err)
 
 	if featureflag.TxAtomicRepositoryCreation.IsEnabled(ctx) {
-		var actualVotes []string
-		for _, vote := range votes {
-			actualVotes = append(actualVotes, vote.String())
+		createVote := func(hash string, phase voting.Phase) transaction.PhasedVote {
+			vote, err := voting.VoteFromString(hash)
+			require.NoError(t, err)
+			return transaction.PhasedVote{Vote: vote, Phase: phase}
 		}
 
 		// While the following votes are opaque to us, this doesn't really matter. All we do
 		// care about is that they're stable.
-		require.Equal(t, []string{
+		require.Equal(t, []transaction.PhasedVote{
 			// These are the votes created by git-fetch(1).
-			"47553c06f575f757ad56ef3216c59804b72aa4a6",
-			"47553c06f575f757ad56ef3216c59804b72aa4a6",
+			createVote("47553c06f575f757ad56ef3216c59804b72aa4a6", voting.Prepared),
+			createVote("47553c06f575f757ad56ef3216c59804b72aa4a6", voting.Committed),
 			// And this is the manual votes we compute by walking the repository.
-			"da39a3ee5e6b4b0d3255bfef95601890afd80709",
-			"da39a3ee5e6b4b0d3255bfef95601890afd80709",
-		}, actualVotes)
+			createVote("da39a3ee5e6b4b0d3255bfef95601890afd80709", voting.Prepared),
+			createVote("da39a3ee5e6b4b0d3255bfef95601890afd80709", voting.Committed),
+		}, txManager.Votes())
 		return
 	}
 
-	var votingInput []string
-
 	// This accounts for the first two votes via git-clone(1). Given that git-clone(1) creates
 	// all references in a single reference transaction, the hook is executed twice for all
 	// fetched references (once for "prepare", once for "commit").
-	votingInput = append(votingInput,
-		fmt.Sprintf("%s %s refs/heads/feature\n%s %s refs/heads/master\n", git.ZeroOID, featureOID, git.ZeroOID, masterOID),
-		fmt.Sprintf("%s %s refs/heads/feature\n%s %s refs/heads/master\n", git.ZeroOID, featureOID, git.ZeroOID, masterOID),
-	)
+	voteFromCloning := []byte(fmt.Sprintf("%s %s refs/heads/feature\n%s %s refs/heads/master\n", git.ZeroOID, featureOID, git.ZeroOID, masterOID))
 
 	// Keep-around references are not fetched via git-clone(1) because non-mirror clones only
 	// fetch branches and tags. These additional references are thus obtained via git-fetch(1).
 	// Given that we use the `--atomic` flag for git-fetch(1), all reference updates will be in
 	// a single transaction and we thus expect exactly two votes (once for "prepare", once for
 	// "commit").
-	votingInput = append(votingInput,
-		fmt.Sprintf("%s %s refs/keep-around/2\n%s %s refs/keep-around/1\n", git.ZeroOID, masterOID, git.ZeroOID, masterOID),
-		fmt.Sprintf("%s %s refs/keep-around/2\n%s %s refs/keep-around/1\n", git.ZeroOID, masterOID, git.ZeroOID, masterOID),
-	)
-
-	var expectedVotes []voting.Vote
-	for _, expectedVote := range votingInput {
-		expectedVotes = append(expectedVotes, voting.VoteFromData([]byte(expectedVote)))
-	}
-
-	require.Equal(t, votes, expectedVotes)
+	voteFromFetching := []byte(fmt.Sprintf("%s %s refs/keep-around/2\n%s %s refs/keep-around/1\n", git.ZeroOID, masterOID, git.ZeroOID, masterOID))
+
+	require.Equal(t, []transaction.PhasedVote{
+		{Vote: voting.VoteFromData(voteFromCloning), Phase: voting.Prepared},
+		{Vote: voting.VoteFromData(voteFromCloning), Phase: voting.Committed},
+		{Vote: voting.VoteFromData(voteFromFetching), Phase: voting.Prepared},
+		{Vote: voting.VoteFromData(voteFromFetching), Phase: voting.Committed},
+	}, txManager.Votes())
 }
 
 func TestCreateRepositoryFromBundle_invalidBundle(t *testing.T) {
diff --git a/internal/gitaly/service/repository/create_repository_test.go b/internal/gitaly/service/repository/create_repository_test.go
index 813259a4f..6e2a6df7c 100644
--- a/internal/gitaly/service/repository/create_repository_test.go
+++ b/internal/gitaly/service/repository/create_repository_test.go
@@ -150,26 +150,16 @@ func TestCreateRepository_transactional(t *testing.T) {
 }
 
 func testCreateRepositoryTransactional(t *testing.T, ctx context.Context) {
-	var actualVote voting.Vote
-	var called int
-
-	mockTxManager := transaction.MockManager{
-		VoteFn: func(ctx context.Context, tx txinfo.Transaction, v voting.Vote) error {
-			actualVote = v
-			called++
-			return nil
-		},
-	}
+	txManager := transaction.NewTrackingManager()
 
-	cfg, client := setupRepositoryServiceWithoutRepo(t, testserver.WithTransactionManager(&mockTxManager))
+	cfg, client := setupRepositoryServiceWithoutRepo(t, testserver.WithTransactionManager(txManager))
 
 	ctx, err := txinfo.InjectTransaction(ctx, 1, "node", true)
 	require.NoError(t, err)
 	ctx = metadata.IncomingToOutgoing(ctx)
 
 	t.Run("initial creation without refs", func(t *testing.T) {
-		called = 0
-		actualVote = voting.Vote{}
+		txManager.Reset()
 
 		repo := &gitalypb.Repository{
 			StorageName:  cfg.Storages[0].Name,
@@ -180,16 +170,16 @@ func testCreateRepositoryTransactional(t *testing.T, ctx context.Context) {
 
 		require.DirExists(t, filepath.Join(cfg.Storages[0].Path, getReplicaPath(ctx, t, client, repo)))
 		if featureflag.TxAtomicRepositoryCreation.IsEnabled(ctx) {
-			require.Equal(t, 2, called, "expected transactional vote")
+			require.Equal(t, 2, len(txManager.Votes()), "expected transactional vote")
 		} else {
-			require.Equal(t, 1, called, "expected transactional vote")
-			require.Equal(t, voting.VoteFromData([]byte{}), actualVote)
+			require.Equal(t, []transaction.PhasedVote{
+				{Vote: voting.VoteFromData([]byte{}), Phase: voting.UnknownPhase},
+			}, txManager.Votes())
 		}
 	})
 
 	t.Run("idempotent creation with preexisting refs", func(t *testing.T) {
-		called = 0
-		actualVote = voting.Vote{}
+		txManager.Reset()
 
 		// The above test creates the second repository on the server. As this test can run with Praefect in front of it,
 		// we'll use the next replica path Praefect will assign in order to ensure this repository creation conflicts even
@@ -212,8 +202,9 @@ func testCreateRepositoryTransactional(t *testing.T, ctx context.Context) {
 		refs := gittest.Exec(t, cfg, "-C", repoPath, "for-each-ref")
 		require.NotEmpty(t, refs)
 
-		require.Equal(t, 1, called, "expected transactional vote")
-		require.Equal(t, voting.VoteFromData(refs), actualVote)
+		require.Equal(t, []transaction.PhasedVote{
+			{Vote: voting.VoteFromData(refs), Phase: voting.UnknownPhase},
+		}, txManager.Votes())
 	})
 }
 
diff --git a/internal/gitaly/service/repository/fetch_remote.go b/internal/gitaly/service/repository/fetch_remote.go
index 81845a363..f7849d838 100644
--- a/internal/gitaly/service/repository/fetch_remote.go
+++ b/internal/gitaly/service/repository/fetch_remote.go
@@ -114,7 +114,7 @@ func (s *server) FetchRemote(ctx context.Context, req *gitalypb.FetchRemoteReque
 			return err
 		}
 
-		return s.txManager.Vote(ctx, tx, vote)
+		return s.txManager.Vote(ctx, tx, vote, voting.UnknownPhase)
 	}); err != nil {
 		return nil, status.Errorf(codes.Aborted, "failed vote on refs: %v", err)
 	}
diff --git a/internal/gitaly/service/repository/fetch_remote_test.go b/internal/gitaly/service/repository/fetch_remote_test.go
index 56355d45e..8f86bcac7 100644
--- a/internal/gitaly/service/repository/fetch_remote_test.go
+++ b/internal/gitaly/service/repository/fetch_remote_test.go
@@ -1,7 +1,6 @@
 package repository
 
 import (
-	"context"
 	"fmt"
 	"net/http"
 	"net/http/httptest"
@@ -24,7 +23,6 @@ import (
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testcfg"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testserver"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/txinfo"
-	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/voting"
 	"gitlab.com/gitlab-org/gitaly/v14/proto/go/gitalypb"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
@@ -184,21 +182,11 @@ func TestFetchRemote_withDefaultRefmaps(t *testing.T) {
 	require.Equal(t, sourceRefs, targetRefs)
 }
 
-type mockTxManager struct {
-	transaction.Manager
-	votes int
-}
-
-func (m *mockTxManager) Vote(context.Context, txinfo.Transaction, voting.Vote) error {
-	m.votes++
-	return nil
-}
-
 func TestFetchRemote_transaction(t *testing.T) {
 	t.Parallel()
 	sourceCfg, _, sourceRepoPath := testcfg.BuildWithRepo(t)
 
-	txManager := &mockTxManager{}
+	txManager := transaction.NewTrackingManager()
 	addr := testserver.RunGitalyServer(t, sourceCfg, nil, func(srv *grpc.Server, deps *service.Dependencies) {
 		gitalypb.RegisterRepositoryServiceServer(srv, NewServer(
 			deps.GetCfg(),
@@ -223,7 +211,7 @@ func TestFetchRemote_transaction(t *testing.T) {
 	require.NoError(t, err)
 	ctx = metadata.IncomingToOutgoing(ctx)
 
-	require.Equal(t, 0, txManager.votes)
+	require.Equal(t, 0, len(txManager.Votes()))
 
 	_, err = client.FetchRemote(ctx, &gitalypb.FetchRemoteRequest{
 		Repository: targetRepoProto,
@@ -233,7 +221,7 @@ func TestFetchRemote_transaction(t *testing.T) {
 	})
 	require.NoError(t, err)
 
-	require.Equal(t, 1, txManager.votes)
+	require.Equal(t, 1, len(txManager.Votes()))
 }
 
 func TestFetchRemote_prune(t *testing.T) {
diff --git a/internal/gitaly/service/repository/midx_test.go b/internal/gitaly/service/repository/midx_test.go
index 03db17ff1..b160f02d1 100644
--- a/internal/gitaly/service/repository/midx_test.go
+++ b/internal/gitaly/service/repository/midx_test.go
@@ -20,7 +20,6 @@ import (
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testserver"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/txinfo"
-	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/voting"
 	"gitlab.com/gitlab-org/gitaly/v14/proto/go/gitalypb"
 	"google.golang.org/grpc/peer"
 )
@@ -118,13 +117,7 @@ func TestMidxRepack_transactional(t *testing.T) {
 	ctx, cancel := testhelper.Context()
 	defer cancel()
 
-	votes := 0
-	txManager := &transaction.MockManager{
-		VoteFn: func(context.Context, txinfo.Transaction, voting.Vote) error {
-			votes++
-			return nil
-		},
-	}
+	txManager := transaction.NewTrackingManager()
 
 	cfg, repo, repoPath, client := setupRepositoryService(t, testserver.WithTransactionManager(txManager))
 
@@ -140,7 +133,7 @@ func TestMidxRepack_transactional(t *testing.T) {
 	})
 	require.NoError(t, err)
 
-	require.Equal(t, 2, votes)
+	require.Equal(t, 2, len(txManager.Votes()))
 
 	multiPackIndex := gittest.Exec(t, cfg, "-C", repoPath, "config", "core.multiPackIndex")
 	require.Equal(t, "true", text.ChompBytes(multiPackIndex))
diff --git a/internal/gitaly/service/repository/remove.go b/internal/gitaly/service/repository/remove.go
index c7befa398..e8a00efd7 100644
--- a/internal/gitaly/service/repository/remove.go
+++ b/internal/gitaly/service/repository/remove.go
@@ -84,7 +84,7 @@ func (s *server) RemoveRepository(ctx context.Context, in *gitalypb.RemoveReposi
 			return nil, helper.ErrInternalf("re-statting repository: %w", err)
 		}
 
-		if err := s.voteOnAction(ctx, repo, preRemove); err != nil {
+		if err := s.voteOnAction(ctx, repo, voting.Prepared); err != nil {
 			return nil, helper.ErrInternalf("vote on rename: %v", err)
 		}
 
@@ -99,11 +99,11 @@ func (s *server) RemoveRepository(ctx context.Context, in *gitalypb.RemoveReposi
 			return nil, helper.ErrInternalf("removing repository: %w", err)
 		}
 
-		if err := s.voteOnAction(ctx, repo, postRemove); err != nil {
+		if err := s.voteOnAction(ctx, repo, voting.Committed); err != nil {
 			return nil, helper.ErrInternalf("vote on finalizing: %v", err)
 		}
 	} else {
-		if err := s.voteOnAction(ctx, repo, preRemove); err != nil {
+		if err := s.voteOnAction(ctx, repo, voting.Prepared); err != nil {
 			return nil, helper.ErrInternalf("vote on rename: %v", err)
 		}
 
@@ -121,7 +121,7 @@ func (s *server) RemoveRepository(ctx context.Context, in *gitalypb.RemoveReposi
 			return nil, helper.ErrInternal(err)
 		}
 
-		if err := s.voteOnAction(ctx, repo, postRemove); err != nil {
+		if err := s.voteOnAction(ctx, repo, voting.Committed); err != nil {
 			return nil, helper.ErrInternalf("vote on finalizing: %v", err)
 		}
 	}
@@ -129,26 +129,19 @@ func (s *server) RemoveRepository(ctx context.Context, in *gitalypb.RemoveReposi
 	return &gitalypb.RemoveRepositoryResponse{}, nil
 }
 
-type removalStep int
-
-const (
-	preRemove = removalStep(iota)
-	postRemove
-)
-
-func (s *server) voteOnAction(ctx context.Context, repo *gitalypb.Repository, step removalStep) error {
+func (s *server) voteOnAction(ctx context.Context, repo *gitalypb.Repository, phase voting.Phase) error {
 	return transaction.RunOnContext(ctx, func(tx txinfo.Transaction) error {
 		var voteStep string
-		switch step {
-		case preRemove:
+		switch phase {
+		case voting.Prepared:
 			voteStep = "pre-remove"
-		case postRemove:
+		case voting.Committed:
 			voteStep = "post-remove"
 		default:
-			return fmt.Errorf("invalid removal step: %d", step)
+			return fmt.Errorf("invalid removal step: %d", phase)
 		}
 
 		vote := fmt.Sprintf("%s %s", voteStep, repo.GetRelativePath())
-		return s.txManager.Vote(ctx, tx, voting.VoteFromData([]byte(vote)))
+		return s.txManager.Vote(ctx, tx, voting.VoteFromData([]byte(vote)), phase)
 	})
 }
diff --git a/internal/gitaly/service/repository/util.go b/internal/gitaly/service/repository/util.go
index 50a1182b3..dda214eb1 100644
--- a/internal/gitaly/service/repository/util.go
+++ b/internal/gitaly/service/repository/util.go
@@ -177,7 +177,7 @@ func (s *server) createRepository(
 		return helper.ErrAlreadyExistsf("repository exists already")
 	}
 
-	if err := transaction.VoteOnContext(ctx, s.txManager, vote); err != nil {
+	if err := transaction.VoteOnContext(ctx, s.txManager, vote, voting.Prepared); err != nil {
 		return helper.ErrFailedPreconditionf("preparatory vote: %w", err)
 	}
 
@@ -187,7 +187,7 @@ func (s *server) createRepository(
 		return fmt.Errorf("moving repository into place: %w", err)
 	}
 
-	if err := transaction.VoteOnContext(ctx, s.txManager, vote); err != nil {
+	if err := transaction.VoteOnContext(ctx, s.txManager, vote, voting.Committed); err != nil {
 		return helper.ErrFailedPreconditionf("committing vote: %w", err)
 	}
 
diff --git a/internal/gitaly/service/repository/util_test.go b/internal/gitaly/service/repository/util_test.go
index 2e4602a63..48ccebd15 100644
--- a/internal/gitaly/service/repository/util_test.go
+++ b/internal/gitaly/service/repository/util_test.go
@@ -44,7 +44,7 @@ func TestCreateRepository(t *testing.T) {
 		gitCmdFactory: gitCmdFactory,
 	}
 
-	votes := 0
+	var votesByPhase map[voting.Phase]int
 
 	for _, tc := range []struct {
 		desc   string
@@ -136,21 +136,24 @@ func TestCreateRepository(t *testing.T) {
 			desc:          "successful transaction",
 			transactional: true,
 			setup: func(t *testing.T, repo *gitalypb.Repository, repoPath string) {
-				votes = 0
-				txManager.VoteFn = func(context.Context, txinfo.Transaction, voting.Vote) error {
-					votes++
+				votesByPhase = map[voting.Phase]int{}
+				txManager.VoteFn = func(_ context.Context, _ txinfo.Transaction, _ voting.Vote, phase voting.Phase) error {
+					votesByPhase[phase]++
 					return nil
 				}
 			},
 			verify: func(t *testing.T, tempRepo *gitalypb.Repository, tempRepoPath string, realRepo *gitalypb.Repository, realRepoPath string) {
-				require.Equal(t, 2, votes)
+				require.Equal(t, map[voting.Phase]int{
+					voting.Prepared:  1,
+					voting.Committed: 1,
+				}, votesByPhase)
 			},
 		},
 		{
 			desc:          "failing preparatory vote",
 			transactional: true,
 			setup: func(t *testing.T, repo *gitalypb.Repository, repoPath string) {
-				txManager.VoteFn = func(context.Context, txinfo.Transaction, voting.Vote) error {
+				txManager.VoteFn = func(context.Context, txinfo.Transaction, voting.Vote, voting.Phase) error {
 					return errors.New("vote failed")
 				}
 			},
@@ -164,10 +167,8 @@ func TestCreateRepository(t *testing.T) {
 			desc:          "failing post-commit vote",
 			transactional: true,
 			setup: func(t *testing.T, repo *gitalypb.Repository, repoPath string) {
-				votes = 0
-				txManager.VoteFn = func(context.Context, txinfo.Transaction, voting.Vote) error {
-					votes++
-					if votes == 1 {
+				txManager.VoteFn = func(_ context.Context, _ txinfo.Transaction, _ voting.Vote, phase voting.Phase) error {
+					if phase == voting.Prepared {
 						return nil
 					}
 					return errors.New("vote failed")
@@ -196,7 +197,7 @@ func TestCreateRepository(t *testing.T) {
 				require.NoError(t, err)
 				require.NoError(t, lock.Close())
 
-				txManager.VoteFn = func(context.Context, txinfo.Transaction, voting.Vote) error {
+				txManager.VoteFn = func(context.Context, txinfo.Transaction, voting.Vote, voting.Phase) error {
 					require.FailNow(t, "no votes should have happened")
 					return nil
 				}
diff --git a/internal/gitaly/service/ssh/receive_pack.go b/internal/gitaly/service/ssh/receive_pack.go
index 4e82eddc4..80c359e03 100644
--- a/internal/gitaly/service/ssh/receive_pack.go
+++ b/internal/gitaly/service/ssh/receive_pack.go
@@ -100,7 +100,7 @@ func (s *server) sshReceivePack(stream gitalypb.SSHService_SSHReceivePackServer,
 	// ensure there's always at least one vote. In case there was diverging behaviour in
 	// git-receive-pack(1) which led to a different outcome across voters, then this final vote
 	// would fail because the sequence of votes would be different.
-	if err := transaction.VoteOnContext(ctx, s.txManager, voting.Vote{}); err != nil {
+	if err := transaction.VoteOnContext(ctx, s.txManager, voting.Vote{}, voting.Committed); err != nil {
 		return status.Errorf(codes.Aborted, "final transactional vote: %v", err)
 	}
 
diff --git a/internal/gitaly/service/ssh/receive_pack_test.go b/internal/gitaly/service/ssh/receive_pack_test.go
index 6c27ae7d8..56d9ac5c3 100644
--- a/internal/gitaly/service/ssh/receive_pack_test.go
+++ b/internal/gitaly/service/ssh/receive_pack_test.go
@@ -2,7 +2,6 @@ package ssh
 
 import (
 	"bytes"
-	"context"
 	"fmt"
 	"io"
 	"os"
@@ -29,7 +28,6 @@ import (
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testcfg"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/testhelper/testserver"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/txinfo"
-	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/voting"
 	"gitlab.com/gitlab-org/gitaly/v14/proto/go/gitalypb"
 	"gitlab.com/gitlab-org/gitaly/v14/streamio"
 	"google.golang.org/grpc/codes"
@@ -282,15 +280,9 @@ func TestReceivePackTransactional(t *testing.T) {
 
 	testcfg.BuildGitalyHooks(t, cfg)
 
-	var votes int
-	serverSocketPath := runSSHServer(t, cfg, testserver.WithTransactionManager(
-		&transaction.MockManager{
-			VoteFn: func(context.Context, txinfo.Transaction, voting.Vote) error {
-				votes++
-				return nil
-			},
-		},
-	))
+	txManager := transaction.NewTrackingManager()
+
+	serverSocketPath := runSSHServer(t, cfg, testserver.WithTransactionManager(txManager))
 
 	client, conn := newSSHClient(t, serverSocketPath)
 	defer conn.Close()
@@ -435,7 +427,7 @@ func TestReceivePackTransactional(t *testing.T) {
 		},
 	} {
 		t.Run(tc.desc, func(t *testing.T) {
-			votes = 0
+			txManager.Reset()
 
 			var request bytes.Buffer
 			for i, command := range tc.commands {
@@ -480,7 +472,7 @@ func TestReceivePackTransactional(t *testing.T) {
 					require.Equal(t, expectedOID, actualOID.String())
 				}
 			}
-			require.Equal(t, tc.expectedVotes, votes)
+			require.Equal(t, tc.expectedVotes, len(txManager.Votes()))
 		})
 	}
 }
diff --git a/internal/gitaly/transaction/manager.go b/internal/gitaly/transaction/manager.go
index e53088115..d7e2a0993 100644
--- a/internal/gitaly/transaction/manager.go
+++ b/internal/gitaly/transaction/manager.go
@@ -47,7 +47,7 @@ var (
 type Manager interface {
 	// Vote casts a vote on the given transaction which is hosted by the
 	// given Praefect server.
-	Vote(context.Context, txinfo.Transaction, voting.Vote) error
+	Vote(context.Context, txinfo.Transaction, voting.Vote, voting.Phase) error
 
 	// Stop gracefully stops the given transaction which is hosted by the
 	// given Praefect server.
@@ -97,7 +97,12 @@ func (m *PoolManager) getTransactionClient(ctx context.Context, tx txinfo.Transa
 }
 
 // Vote connects to the given server and casts vote as a vote for the transaction identified by tx.
-func (m *PoolManager) Vote(ctx context.Context, tx txinfo.Transaction, vote voting.Vote) error {
+func (m *PoolManager) Vote(
+	ctx context.Context,
+	tx txinfo.Transaction,
+	vote voting.Vote,
+	phase voting.Phase,
+) error {
 	client, err := m.getTransactionClient(ctx, tx)
 	if err != nil {
 		return err
@@ -118,6 +123,7 @@ func (m *PoolManager) Vote(ctx context.Context, tx txinfo.Transaction, vote voti
 		TransactionId:        tx.ID,
 		Node:                 tx.Node,
 		ReferenceUpdatesHash: vote.Bytes(),
+		Phase:                phase.ToProto(),
 	})
 	if err != nil {
 		// Add some additional context to cancellation errors so that
diff --git a/internal/gitaly/transaction/manager_test.go b/internal/gitaly/transaction/manager_test.go
index 6239f0ab2..eb67aa769 100644
--- a/internal/gitaly/transaction/manager_test.go
+++ b/internal/gitaly/transaction/manager_test.go
@@ -63,21 +63,64 @@ func TestPoolManager_Vote(t *testing.T) {
 		desc        string
 		transaction txinfo.Transaction
 		vote        voting.Vote
+		phase       voting.Phase
 		voteFn      func(*testing.T, *gitalypb.VoteTransactionRequest) (*gitalypb.VoteTransactionResponse, error)
 		expectedErr error
 	}{
 		{
-			desc: "successful vote",
+			desc: "successful unknown vote",
 			transaction: txinfo.Transaction{
 				BackchannelID: backchannelID,
 				ID:            1,
 				Node:          "node",
 			},
-			vote: voting.VoteFromData([]byte("foobar")),
+			vote:  voting.VoteFromData([]byte("foobar")),
+			phase: voting.UnknownPhase,
 			voteFn: func(t *testing.T, request *gitalypb.VoteTransactionRequest) (*gitalypb.VoteTransactionResponse, error) {
 				require.Equal(t, uint64(1), request.TransactionId)
 				require.Equal(t, "node", request.Node)
 				require.Equal(t, request.ReferenceUpdatesHash, voting.VoteFromData([]byte("foobar")).Bytes())
+				require.Equal(t, gitalypb.VoteTransactionRequest_UNKNOWN_PHASE, request.Phase)
+
+				return &gitalypb.VoteTransactionResponse{
+					State: gitalypb.VoteTransactionResponse_COMMIT,
+				}, nil
+			},
+		},
+		{
+			desc: "successful prepared vote",
+			transaction: txinfo.Transaction{
+				BackchannelID: backchannelID,
+				ID:            1,
+				Node:          "node",
+			},
+			vote:  voting.VoteFromData([]byte("foobar")),
+			phase: voting.Prepared,
+			voteFn: func(t *testing.T, request *gitalypb.VoteTransactionRequest) (*gitalypb.VoteTransactionResponse, error) {
+				require.Equal(t, uint64(1), request.TransactionId)
+				require.Equal(t, "node", request.Node)
+				require.Equal(t, request.ReferenceUpdatesHash, voting.VoteFromData([]byte("foobar")).Bytes())
+				require.Equal(t, gitalypb.VoteTransactionRequest_PREPARED_PHASE, request.Phase)
+
+				return &gitalypb.VoteTransactionResponse{
+					State: gitalypb.VoteTransactionResponse_COMMIT,
+				}, nil
+			},
+		},
+		{
+			desc: "successful committed vote",
+			transaction: txinfo.Transaction{
+				BackchannelID: backchannelID,
+				ID:            1,
+				Node:          "node",
+			},
+			vote:  voting.VoteFromData([]byte("foobar")),
+			phase: voting.Committed,
+			voteFn: func(t *testing.T, request *gitalypb.VoteTransactionRequest) (*gitalypb.VoteTransactionResponse, error) {
+				require.Equal(t, uint64(1), request.TransactionId)
+				require.Equal(t, "node", request.Node)
+				require.Equal(t, request.ReferenceUpdatesHash, voting.VoteFromData([]byte("foobar")).Bytes())
+				require.Equal(t, gitalypb.VoteTransactionRequest_COMMITTED_PHASE, request.Phase)
 
 				return &gitalypb.VoteTransactionResponse{
 					State: gitalypb.VoteTransactionResponse_COMMIT,
@@ -124,7 +167,7 @@ func TestPoolManager_Vote(t *testing.T) {
 				return tc.voteFn(t, request)
 			}
 
-			err := manager.Vote(ctx, tc.transaction, tc.vote)
+			err := manager.Vote(ctx, tc.transaction, tc.vote, tc.phase)
 			testhelper.RequireGrpcError(t, tc.expectedErr, err)
 		})
 	}
diff --git a/internal/gitaly/transaction/mock.go b/internal/gitaly/transaction/mock.go
index 101d4b291..10ad6efdf 100644
--- a/internal/gitaly/transaction/mock.go
+++ b/internal/gitaly/transaction/mock.go
@@ -3,6 +3,7 @@ package transaction
 import (
 	"context"
 	"errors"
+	"sync"
 
 	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/txinfo"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/transaction/voting"
@@ -10,16 +11,16 @@ import (
 
 // MockManager is a mock Manager for use in tests.
 type MockManager struct {
-	VoteFn func(context.Context, txinfo.Transaction, voting.Vote) error
+	VoteFn func(context.Context, txinfo.Transaction, voting.Vote, voting.Phase) error
 	StopFn func(context.Context, txinfo.Transaction) error
 }
 
 // Vote calls the MockManager's Vote function, if set. Otherwise, it returns an error.
-func (m *MockManager) Vote(ctx context.Context, tx txinfo.Transaction, vote voting.Vote) error {
+func (m *MockManager) Vote(ctx context.Context, tx txinfo.Transaction, vote voting.Vote, phase voting.Phase) error {
 	if m.VoteFn == nil {
 		return errors.New("mock does not implement Vote function")
 	}
-	return m.VoteFn(ctx, tx, vote)
+	return m.VoteFn(ctx, tx, vote, phase)
 }
 
 // Stop calls the MockManager's Stop function, if set. Otherwise, it returns an error.
@@ -29,3 +30,50 @@ func (m *MockManager) Stop(ctx context.Context, tx txinfo.Transaction) error {
 	}
 	return m.StopFn(ctx, tx)
 }
+
+// PhasedVote is used to keep track of votes and the phase they were cast in.
+type PhasedVote struct {
+	Vote  voting.Vote
+	Phase voting.Phase
+}
+
+// TrackingManager is a transaction manager which tracks all votes. Voting functions never return
+// an error.
+type TrackingManager struct {
+	MockManager
+
+	votesLock sync.Mutex
+	votes     []PhasedVote
+}
+
+// NewTrackingManager creates a new TrackingManager which is ready for use.
+func NewTrackingManager() *TrackingManager {
+	manager := &TrackingManager{}
+
+	manager.VoteFn = func(_ context.Context, _ txinfo.Transaction, vote voting.Vote, phase voting.Phase) error {
+		manager.votesLock.Lock()
+		defer manager.votesLock.Unlock()
+		manager.votes = append(manager.votes, PhasedVote{Vote: vote, Phase: phase})
+		return nil
+	}
+
+	return manager
+}
+
+// Votes returns a copy of all votes which have been cast.
+func (m *TrackingManager) Votes() []PhasedVote {
+	m.votesLock.Lock()
+	defer m.votesLock.Unlock()
+
+	votes := make([]PhasedVote, len(m.votes))
+	copy(votes, m.votes)
+
+	return votes
+}
+
+// Reset resets all votes which have been recorded up to this point.
+func (m *TrackingManager) Reset() {
+	m.votesLock.Lock()
+	defer m.votesLock.Unlock()
+	m.votes = nil
+}
diff --git a/internal/gitaly/transaction/voting.go b/internal/gitaly/transaction/voting.go
index 071d944a8..d5ed0683f 100644
--- a/internal/gitaly/transaction/voting.go
+++ b/internal/gitaly/transaction/voting.go
@@ -25,9 +25,9 @@ func RunOnContext(ctx context.Context, fn func(txinfo.Transaction) error) error
 }
 
 // VoteOnContext casts the vote on a transaction identified by the context, if there is any.
-func VoteOnContext(ctx context.Context, m Manager, vote voting.Vote) error {
+func VoteOnContext(ctx context.Context, m Manager, vote voting.Vote, phase voting.Phase) error {
 	return RunOnContext(ctx, func(transaction txinfo.Transaction) error {
-		return m.Vote(ctx, transaction, vote)
+		return m.Vote(ctx, transaction, vote, phase)
 	})
 }
 
@@ -56,7 +56,7 @@ func CommitLockedFile(ctx context.Context, m Manager, writer *safe.LockingFileWr
 			return fmt.Errorf("computing vote for locked file: %w", err)
 		}
 
-		if err := m.Vote(ctx, tx, vote); err != nil {
+		if err := m.Vote(ctx, tx, vote, voting.Prepared); err != nil {
 			return fmt.Errorf("preimage vote: %w", err)
 		}
 
@@ -69,7 +69,7 @@ func CommitLockedFile(ctx context.Context, m Manager, writer *safe.LockingFileWr
 		return fmt.Errorf("committing file: %w", err)
 	}
 
-	if err := VoteOnContext(ctx, m, vote); err != nil {
+	if err := VoteOnContext(ctx, m, vote, voting.Committed); err != nil {
 		return fmt.Errorf("postimage vote: %w", err)
 	}
 
diff --git a/internal/gitaly/transaction/voting_test.go b/internal/gitaly/transaction/voting_test.go
index 434c9374e..dc195c9f4 100644
--- a/internal/gitaly/transaction/voting_test.go
+++ b/internal/gitaly/transaction/voting_test.go
@@ -76,10 +76,10 @@ func TestVoteOnContext(t *testing.T) {
 		AuthInfo: backchannel.WithID(nil, 1234),
 	}
 
-	vote := voting.VoteFromData([]byte("1"))
+	expectedVote := voting.VoteFromData([]byte("1"))
 
 	t.Run("without transaction", func(t *testing.T) {
-		require.NoError(t, VoteOnContext(ctx, &MockManager{}, voting.Vote{}))
+		require.NoError(t, VoteOnContext(ctx, &MockManager{}, voting.Vote{}, voting.Prepared))
 	})
 
 	t.Run("successful vote", func(t *testing.T) {
@@ -89,7 +89,7 @@ func TestVoteOnContext(t *testing.T) {
 
 		callbackExecuted := false
 		require.NoError(t, VoteOnContext(ctx, &MockManager{
-			VoteFn: func(ctx context.Context, tx txinfo.Transaction, vote voting.Vote) error {
+			VoteFn: func(ctx context.Context, tx txinfo.Transaction, vote voting.Vote, phase voting.Phase) error {
 				require.Equal(t, txinfo.Transaction{
 					ID:            5678,
 					Node:          "node",
@@ -97,9 +97,11 @@ func TestVoteOnContext(t *testing.T) {
 					BackchannelID: 1234,
 				}, tx)
 				callbackExecuted = true
+				require.Equal(t, expectedVote, vote)
+				require.Equal(t, voting.Prepared, phase)
 				return nil
 			},
-		}, vote))
+		}, expectedVote, voting.Prepared))
 		require.True(t, callbackExecuted, "callback should have been executed")
 	})
 
@@ -110,10 +112,10 @@ func TestVoteOnContext(t *testing.T) {
 
 		expectedErr := fmt.Errorf("any error")
 		require.Equal(t, expectedErr, VoteOnContext(ctx, &MockManager{
-			VoteFn: func(ctx context.Context, tx txinfo.Transaction, vote voting.Vote) error {
+			VoteFn: func(context.Context, txinfo.Transaction, voting.Vote, voting.Phase) error {
 				return expectedErr
 			},
-		}, vote))
+		}, expectedVote, voting.Prepared))
 	})
 }
 
@@ -151,7 +153,7 @@ func TestCommitLockedFile(t *testing.T) {
 
 		calls := 0
 		require.NoError(t, CommitLockedFile(ctx, &MockManager{
-			VoteFn: func(ctx context.Context, tx txinfo.Transaction, vote voting.Vote) error {
+			VoteFn: func(ctx context.Context, tx txinfo.Transaction, vote voting.Vote, phase voting.Phase) error {
 				require.Equal(t, txinfo.Transaction{
 					ID:            5678,
 					Node:          "node",
@@ -160,6 +162,16 @@ func TestCommitLockedFile(t *testing.T) {
 				}, tx)
 				require.Equal(t, voting.VoteFromData([]byte("contents")), vote)
 				calls++
+
+				switch calls {
+				case 1:
+					require.Equal(t, voting.Prepared, phase)
+				case 2:
+					require.Equal(t, voting.Committed, phase)
+				default:
+					require.FailNow(t, "unexpected voting phase %q", phase)
+				}
+
 				return nil
 			},
 		}, writer))
@@ -177,7 +189,7 @@ func TestCommitLockedFile(t *testing.T) {
 		require.NoError(t, err)
 
 		err = CommitLockedFile(ctx, &MockManager{
-			VoteFn: func(context.Context, txinfo.Transaction, voting.Vote) error {
+			VoteFn: func(context.Context, txinfo.Transaction, voting.Vote, voting.Phase) error {
 				return fmt.Errorf("some error")
 			},
 		}, writer)
@@ -195,11 +207,10 @@ func TestCommitLockedFile(t *testing.T) {
 		require.NoError(t, err)
 
 		err = CommitLockedFile(ctx, &MockManager{
-			VoteFn: func(context.Context, txinfo.Transaction, voting.Vote) error {
+			VoteFn: func(context.Context, txinfo.Transaction, voting.Vote, voting.Phase) error {
 				// This shouldn't typically happen given that the file is locked,
 				// but we concurrently update the file after our first vote.
-				require.NoError(t, os.WriteFile(file, []byte("something"),
-					0o666))
+				require.NoError(t, os.WriteFile(file, []byte("something"), 0o666))
 				return nil
 			},
 		}, writer)
diff --git a/internal/transaction/voting/phase.go b/internal/transaction/voting/phase.go
new file mode 100644
index 000000000..fb3922a6c
--- /dev/null
+++ b/internal/transaction/voting/phase.go
@@ -0,0 +1,36 @@
+package voting
+
+import (
+	"fmt"
+
+	"gitlab.com/gitlab-org/gitaly/v14/proto/go/gitalypb"
+)
+
+// Phase is the transactional phase a given vote can be cast on.
+type Phase int
+
+const (
+	// UnknownPhase is the default value. It should not be used.
+	UnknownPhase = Phase(iota)
+	// Prepared is the prepratory phase. The data that is about to change is locked for
+	// concurrent modification, but changes have not yet been written to disk.
+	Prepared
+	// Committed is the committing phase. Data has been committed to disk and will be visible
+	// in all subsequent requests.
+	Committed
+)
+
+// ToProto converts the phase into its Protobuf enum. This function panics if called with an
+// invalid phase.
+func (p Phase) ToProto() gitalypb.VoteTransactionRequest_Phase {
+	switch p {
+	case UnknownPhase:
+		return gitalypb.VoteTransactionRequest_UNKNOWN_PHASE
+	case Prepared:
+		return gitalypb.VoteTransactionRequest_PREPARED_PHASE
+	case Committed:
+		return gitalypb.VoteTransactionRequest_COMMITTED_PHASE
+	default:
+		panic(fmt.Sprintf("unknown phase %q", p))
+	}
+}
diff --git a/internal/transaction/voting/vote.go b/internal/transaction/voting/vote.go
index dcb0fc32e..19412f742 100644
--- a/internal/transaction/voting/vote.go
+++ b/internal/transaction/voting/vote.go
@@ -37,6 +37,16 @@ func VoteFromHash(bytes []byte) (Vote, error) {
 	return vote, nil
 }
 
+// VoteFromString converts the given string representation of the hash into a vote.
+func VoteFromString(s string) (Vote, error) {
+	bytes, err := hex.DecodeString(s)
+	if err != nil {
+		return Vote{}, fmt.Errorf("invalid vote string: %w", err)
+	}
+
+	return VoteFromHash(bytes)
+}
+
 // VoteFromData hashes the given data and converts it to a vote.
 func VoteFromData(data []byte) Vote {
 	return sha1.Sum(data)
diff --git a/internal/transaction/voting/vote_test.go b/internal/transaction/voting/vote_test.go
index 564eb2d84..98acfd509 100644
--- a/internal/transaction/voting/vote_test.go
+++ b/internal/transaction/voting/vote_test.go
@@ -2,7 +2,10 @@ package voting
 
 import (
 	"bytes"
+	"encoding/hex"
+	"errors"
 	"fmt"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -23,6 +26,30 @@ func TestVoteFromHash(t *testing.T) {
 	require.Equal(t, bytes.Repeat([]byte{1}, voteSize), vote.Bytes())
 }
 
+func TestVoteFromString(t *testing.T) {
+	_, err := VoteFromString("")
+	require.Equal(t, fmt.Errorf("invalid vote length 0"), err)
+
+	_, err = VoteFromString("x")
+	require.Error(t, err)
+	var invalidByteError hex.InvalidByteError
+	require.True(t, errors.As(err, &invalidByteError))
+	require.Equal(t, hex.InvalidByteError('x'), invalidByteError)
+
+	_, err = VoteFromString("1234")
+	require.Equal(t, fmt.Errorf("invalid vote length 2"), err)
+
+	_, err = VoteFromString(strings.Repeat("1", (voteSize+1)*2))
+	require.Equal(t, fmt.Errorf("invalid vote length 21"), err)
+
+	vote, err := VoteFromString(strings.Repeat("1", voteSize*2))
+	require.Equal(t, Vote{
+		0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
+		0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
+	}, vote)
+	require.NoError(t, err)
+}
+
 func TestVoteFromData(t *testing.T) {
 	require.Equal(t, Vote{
 		0xda, 0x39, 0xa3, 0xee, 0x5e, 0x6b, 0x4b, 0x0d, 0x32, 0x55,
diff --git a/proto/go/gitalypb/transaction.pb.go b/proto/go/gitalypb/transaction.pb.go
index 24e8aaab8..7910a01d1 100644
--- a/proto/go/gitalypb/transaction.pb.go
+++ b/proto/go/gitalypb/transaction.pb.go
@@ -20,6 +20,63 @@ const (
 	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
 )
 
+type VoteTransactionRequest_Phase int32
+
+const (
+	// UNKNOWN_PHASE is the unknown voting phase. This value has been the
+	// default because phases have been introduced. Eventually, using this
+	// phase will become unsupported.
+	VoteTransactionRequest_UNKNOWN_PHASE VoteTransactionRequest_Phase = 0
+	// PREPARED_PHASE is the prepratory phase. The data that is about to change
+	// is locked for concurrent modification, but changes have not yet been
+	// written to disk.
+	VoteTransactionRequest_PREPARED_PHASE VoteTransactionRequest_Phase = 1
+	// COMMITTED_PHASE is the committing phase. Data has been committed to disk
+	// and will be visible in all subsequent requests.
+	VoteTransactionRequest_COMMITTED_PHASE VoteTransactionRequest_Phase = 2
+)
+
+// Enum value maps for VoteTransactionRequest_Phase.
+var (
+	VoteTransactionRequest_Phase_name = map[int32]string{
+		0: "UNKNOWN_PHASE",
+		1: "PREPARED_PHASE",
+		2: "COMMITTED_PHASE",
+	}
+	VoteTransactionRequest_Phase_value = map[string]int32{
+		"UNKNOWN_PHASE":   0,
+		"PREPARED_PHASE":  1,
+		"COMMITTED_PHASE": 2,
+	}
+)
+
+func (x VoteTransactionRequest_Phase) Enum() *VoteTransactionRequest_Phase {
+	p := new(VoteTransactionRequest_Phase)
+	*p = x
+	return p
+}
+
+func (x VoteTransactionRequest_Phase) String() string {
+	return protoimpl.X.EnumStringOf(x.Descriptor(), protoreflect.EnumNumber(x))
+}
+
+func (VoteTransactionRequest_Phase) Descriptor() protoreflect.EnumDescriptor {
+	return file_transaction_proto_enumTypes[0].Descriptor()
+}
+
+func (VoteTransactionRequest_Phase) Type() protoreflect.EnumType {
+	return &file_transaction_proto_enumTypes[0]
+}
+
+func (x VoteTransactionRequest_Phase) Number() protoreflect.EnumNumber {
+	return protoreflect.EnumNumber(x)
+}
+
+// Deprecated: Use VoteTransactionRequest_Phase.Descriptor instead.
+func (VoteTransactionRequest_Phase) EnumDescriptor() ([]byte, []int) {
+	return file_transaction_proto_rawDescGZIP(), []int{0, 0}
+}
+
 // The outcome of the given transaction telling the client whether the
 // transaction should be committed or rolled back.
 type VoteTransactionResponse_TransactionState int32
@@ -55,11 +112,11 @@ func (x VoteTransactionResponse_TransactionState) String() string {
 }
 
 func (VoteTransactionResponse_TransactionState) Descriptor() protoreflect.EnumDescriptor {
-	return file_transaction_proto_enumTypes[0].Descriptor()
+	return file_transaction_proto_enumTypes[1].Descriptor()
 }
 
 func (VoteTransactionResponse_TransactionState) Type() protoreflect.EnumType {
-	return &file_transaction_proto_enumTypes[0]
+	return &file_transaction_proto_enumTypes[1]
 }
 
 func (x VoteTransactionResponse_TransactionState) Number() protoreflect.EnumNumber {
@@ -83,6 +140,8 @@ type VoteTransactionRequest struct {
 	Node string `protobuf:"bytes,3,opt,name=node,proto3" json:"node,omitempty"`
 	// SHA1 of the references that are to be updated
 	ReferenceUpdatesHash []byte `protobuf:"bytes,4,opt,name=reference_updates_hash,json=referenceUpdatesHash,proto3" json:"reference_updates_hash,omitempty"`
+	// Phase is the voting phase.
+	Phase VoteTransactionRequest_Phase `protobuf:"varint,5,opt,name=phase,proto3,enum=gitaly.VoteTransactionRequest_Phase" json:"phase,omitempty"`
 }
 
 func (x *VoteTransactionRequest) Reset() {
@@ -145,6 +204,13 @@ func (x *VoteTransactionRequest) GetReferenceUpdatesHash() []byte {
 	return nil
 }
 
+func (x *VoteTransactionRequest) GetPhase() VoteTransactionRequest_Phase {
+	if x != nil {
+		return x.Phase
+	}
+	return VoteTransactionRequest_UNKNOWN_PHASE
+}
+
 type VoteTransactionResponse struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
@@ -292,7 +358,7 @@ var file_transaction_proto_rawDesc = []byte{
 	0x0a, 0x11, 0x74, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x2e, 0x70, 0x72,
 	0x6f, 0x74, 0x6f, 0x12, 0x06, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x1a, 0x0a, 0x6c, 0x69, 0x6e,
 	0x74, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x1a, 0x0c, 0x73, 0x68, 0x61, 0x72, 0x65, 0x64, 0x2e,
-	0x70, 0x72, 0x6f, 0x74, 0x6f, 0x22, 0xc3, 0x01, 0x0a, 0x16, 0x56, 0x6f, 0x74, 0x65, 0x54, 0x72,
+	0x70, 0x72, 0x6f, 0x74, 0x6f, 0x22, 0xc4, 0x02, 0x0a, 0x16, 0x56, 0x6f, 0x74, 0x65, 0x54, 0x72,
 	0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74,
 	0x12, 0x38, 0x0a, 0x0a, 0x72, 0x65, 0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x18, 0x01,
 	0x20, 0x01, 0x28, 0x0b, 0x32, 0x12, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x52, 0x65,
@@ -304,43 +370,51 @@ var file_transaction_proto_rawDesc = []byte{
 	0x04, 0x6e, 0x6f, 0x64, 0x65, 0x12, 0x34, 0x0a, 0x16, 0x72, 0x65, 0x66, 0x65, 0x72, 0x65, 0x6e,
 	0x63, 0x65, 0x5f, 0x75, 0x70, 0x64, 0x61, 0x74, 0x65, 0x73, 0x5f, 0x68, 0x61, 0x73, 0x68, 0x18,
 	0x04, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x14, 0x72, 0x65, 0x66, 0x65, 0x72, 0x65, 0x6e, 0x63, 0x65,
-	0x55, 0x70, 0x64, 0x61, 0x74, 0x65, 0x73, 0x48, 0x61, 0x73, 0x68, 0x22, 0x96, 0x01, 0x0a, 0x17,
-	0x56, 0x6f, 0x74, 0x65, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52,
-	0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x12, 0x46, 0x0a, 0x05, 0x73, 0x74, 0x61, 0x74, 0x65,
-	0x18, 0x01, 0x20, 0x01, 0x28, 0x0e, 0x32, 0x30, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e,
-	0x56, 0x6f, 0x74, 0x65, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52,
-	0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x2e, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74,
-	0x69, 0x6f, 0x6e, 0x53, 0x74, 0x61, 0x74, 0x65, 0x52, 0x05, 0x73, 0x74, 0x61, 0x74, 0x65, 0x22,
-	0x33, 0x0a, 0x10, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x53, 0x74,
-	0x61, 0x74, 0x65, 0x12, 0x0a, 0x0a, 0x06, 0x43, 0x4f, 0x4d, 0x4d, 0x49, 0x54, 0x10, 0x00, 0x12,
-	0x09, 0x0a, 0x05, 0x41, 0x42, 0x4f, 0x52, 0x54, 0x10, 0x01, 0x12, 0x08, 0x0a, 0x04, 0x53, 0x54,
-	0x4f, 0x50, 0x10, 0x02, 0x22, 0x79, 0x0a, 0x16, 0x53, 0x74, 0x6f, 0x70, 0x54, 0x72, 0x61, 0x6e,
-	0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x12, 0x38,
-	0x0a, 0x0a, 0x72, 0x65, 0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x18, 0x01, 0x20, 0x01,
-	0x28, 0x0b, 0x32, 0x12, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x52, 0x65, 0x70, 0x6f,
-	0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x42, 0x04, 0x98, 0xc6, 0x2c, 0x01, 0x52, 0x0a, 0x72, 0x65,
-	0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x12, 0x25, 0x0a, 0x0e, 0x74, 0x72, 0x61, 0x6e,
-	0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x5f, 0x69, 0x64, 0x18, 0x02, 0x20, 0x01, 0x28, 0x04,
-	0x52, 0x0d, 0x74, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x49, 0x64, 0x22,
-	0x19, 0x0a, 0x17, 0x53, 0x74, 0x6f, 0x70, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69,
-	0x6f, 0x6e, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x32, 0xc8, 0x01, 0x0a, 0x0e, 0x52,
-	0x65, 0x66, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x12, 0x5a, 0x0a,
-	0x0f, 0x56, 0x6f, 0x74, 0x65, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e,
-	0x12, 0x1e, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x56, 0x6f, 0x74, 0x65, 0x54, 0x72,
-	0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74,
-	0x1a, 0x1f, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x56, 0x6f, 0x74, 0x65, 0x54, 0x72,
-	0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73,
-	0x65, 0x22, 0x06, 0xfa, 0x97, 0x28, 0x02, 0x08, 0x01, 0x12, 0x5a, 0x0a, 0x0f, 0x53, 0x74, 0x6f,
-	0x70, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x12, 0x1e, 0x2e, 0x67,
-	0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x53, 0x74, 0x6f, 0x70, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61,
-	0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x1f, 0x2e, 0x67,
-	0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x53, 0x74, 0x6f, 0x70, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61,
-	0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x22, 0x06, 0xfa,
-	0x97, 0x28, 0x02, 0x08, 0x01, 0x42, 0x34, 0x5a, 0x32, 0x67, 0x69, 0x74, 0x6c, 0x61, 0x62, 0x2e,
-	0x63, 0x6f, 0x6d, 0x2f, 0x67, 0x69, 0x74, 0x6c, 0x61, 0x62, 0x2d, 0x6f, 0x72, 0x67, 0x2f, 0x67,
-	0x69, 0x74, 0x61, 0x6c, 0x79, 0x2f, 0x76, 0x31, 0x34, 0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x2f,
-	0x67, 0x6f, 0x2f, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x70, 0x62, 0x62, 0x06, 0x70, 0x72, 0x6f,
-	0x74, 0x6f, 0x33,
+	0x55, 0x70, 0x64, 0x61, 0x74, 0x65, 0x73, 0x48, 0x61, 0x73, 0x68, 0x12, 0x3a, 0x0a, 0x05, 0x70,
+	0x68, 0x61, 0x73, 0x65, 0x18, 0x05, 0x20, 0x01, 0x28, 0x0e, 0x32, 0x24, 0x2e, 0x67, 0x69, 0x74,
+	0x61, 0x6c, 0x79, 0x2e, 0x56, 0x6f, 0x74, 0x65, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74,
+	0x69, 0x6f, 0x6e, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x2e, 0x50, 0x68, 0x61, 0x73, 0x65,
+	0x52, 0x05, 0x70, 0x68, 0x61, 0x73, 0x65, 0x22, 0x43, 0x0a, 0x05, 0x50, 0x68, 0x61, 0x73, 0x65,
+	0x12, 0x11, 0x0a, 0x0d, 0x55, 0x4e, 0x4b, 0x4e, 0x4f, 0x57, 0x4e, 0x5f, 0x50, 0x48, 0x41, 0x53,
+	0x45, 0x10, 0x00, 0x12, 0x12, 0x0a, 0x0e, 0x50, 0x52, 0x45, 0x50, 0x41, 0x52, 0x45, 0x44, 0x5f,
+	0x50, 0x48, 0x41, 0x53, 0x45, 0x10, 0x01, 0x12, 0x13, 0x0a, 0x0f, 0x43, 0x4f, 0x4d, 0x4d, 0x49,
+	0x54, 0x54, 0x45, 0x44, 0x5f, 0x50, 0x48, 0x41, 0x53, 0x45, 0x10, 0x02, 0x22, 0x96, 0x01, 0x0a,
+	0x17, 0x56, 0x6f, 0x74, 0x65, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e,
+	0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x12, 0x46, 0x0a, 0x05, 0x73, 0x74, 0x61, 0x74,
+	0x65, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0e, 0x32, 0x30, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79,
+	0x2e, 0x56, 0x6f, 0x74, 0x65, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e,
+	0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x2e, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63,
+	0x74, 0x69, 0x6f, 0x6e, 0x53, 0x74, 0x61, 0x74, 0x65, 0x52, 0x05, 0x73, 0x74, 0x61, 0x74, 0x65,
+	0x22, 0x33, 0x0a, 0x10, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x53,
+	0x74, 0x61, 0x74, 0x65, 0x12, 0x0a, 0x0a, 0x06, 0x43, 0x4f, 0x4d, 0x4d, 0x49, 0x54, 0x10, 0x00,
+	0x12, 0x09, 0x0a, 0x05, 0x41, 0x42, 0x4f, 0x52, 0x54, 0x10, 0x01, 0x12, 0x08, 0x0a, 0x04, 0x53,
+	0x54, 0x4f, 0x50, 0x10, 0x02, 0x22, 0x79, 0x0a, 0x16, 0x53, 0x74, 0x6f, 0x70, 0x54, 0x72, 0x61,
+	0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x12,
+	0x38, 0x0a, 0x0a, 0x72, 0x65, 0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x18, 0x01, 0x20,
+	0x01, 0x28, 0x0b, 0x32, 0x12, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x52, 0x65, 0x70,
+	0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x42, 0x04, 0x98, 0xc6, 0x2c, 0x01, 0x52, 0x0a, 0x72,
+	0x65, 0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x12, 0x25, 0x0a, 0x0e, 0x74, 0x72, 0x61,
+	0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x5f, 0x69, 0x64, 0x18, 0x02, 0x20, 0x01, 0x28,
+	0x04, 0x52, 0x0d, 0x74, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x49, 0x64,
+	0x22, 0x19, 0x0a, 0x17, 0x53, 0x74, 0x6f, 0x70, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74,
+	0x69, 0x6f, 0x6e, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x32, 0xc8, 0x01, 0x0a, 0x0e,
+	0x52, 0x65, 0x66, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x12, 0x5a,
+	0x0a, 0x0f, 0x56, 0x6f, 0x74, 0x65, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f,
+	0x6e, 0x12, 0x1e, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x56, 0x6f, 0x74, 0x65, 0x54,
+	0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73,
+	0x74, 0x1a, 0x1f, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x56, 0x6f, 0x74, 0x65, 0x54,
+	0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e,
+	0x73, 0x65, 0x22, 0x06, 0xfa, 0x97, 0x28, 0x02, 0x08, 0x01, 0x12, 0x5a, 0x0a, 0x0f, 0x53, 0x74,
+	0x6f, 0x70, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x12, 0x1e, 0x2e,
+	0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x53, 0x74, 0x6f, 0x70, 0x54, 0x72, 0x61, 0x6e, 0x73,
+	0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x1f, 0x2e,
+	0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x53, 0x74, 0x6f, 0x70, 0x54, 0x72, 0x61, 0x6e, 0x73,
+	0x61, 0x63, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x22, 0x06,
+	0xfa, 0x97, 0x28, 0x02, 0x08, 0x01, 0x42, 0x34, 0x5a, 0x32, 0x67, 0x69, 0x74, 0x6c, 0x61, 0x62,
+	0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x67, 0x69, 0x74, 0x6c, 0x61, 0x62, 0x2d, 0x6f, 0x72, 0x67, 0x2f,
+	0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2f, 0x76, 0x31, 0x34, 0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f,
+	0x2f, 0x67, 0x6f, 0x2f, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x70, 0x62, 0x62, 0x06, 0x70, 0x72,
+	0x6f, 0x74, 0x6f, 0x33,
 }
 
 var (
@@ -355,29 +429,31 @@ func file_transaction_proto_rawDescGZIP() []byte {
 	return file_transaction_proto_rawDescData
 }
 
-var file_transaction_proto_enumTypes = make([]protoimpl.EnumInfo, 1)
+var file_transaction_proto_enumTypes = make([]protoimpl.EnumInfo, 2)
 var file_transaction_proto_msgTypes = make([]protoimpl.MessageInfo, 4)
 var file_transaction_proto_goTypes = []interface{}{
-	(VoteTransactionResponse_TransactionState)(0), // 0: gitaly.VoteTransactionResponse.TransactionState
-	(*VoteTransactionRequest)(nil),                // 1: gitaly.VoteTransactionRequest
-	(*VoteTransactionResponse)(nil),               // 2: gitaly.VoteTransactionResponse
-	(*StopTransactionRequest)(nil),                // 3: gitaly.StopTransactionRequest
-	(*StopTransactionResponse)(nil),               // 4: gitaly.StopTransactionResponse
-	(*Repository)(nil),                            // 5: gitaly.Repository
+	(VoteTransactionRequest_Phase)(0),             // 0: gitaly.VoteTransactionRequest.Phase
+	(VoteTransactionResponse_TransactionState)(0), // 1: gitaly.VoteTransactionResponse.TransactionState
+	(*VoteTransactionRequest)(nil),                // 2: gitaly.VoteTransactionRequest
+	(*VoteTransactionResponse)(nil),               // 3: gitaly.VoteTransactionResponse
+	(*StopTransactionRequest)(nil),                // 4: gitaly.StopTransactionRequest
+	(*StopTransactionResponse)(nil),               // 5: gitaly.StopTransactionResponse
+	(*Repository)(nil),                            // 6: gitaly.Repository
 }
 var file_transaction_proto_depIdxs = []int32{
-	5, // 0: gitaly.VoteTransactionRequest.repository:type_name -> gitaly.Repository
-	0, // 1: gitaly.VoteTransactionResponse.state:type_name -> gitaly.VoteTransactionResponse.TransactionState
-	5, // 2: gitaly.StopTransactionRequest.repository:type_name -> gitaly.Repository
-	1, // 3: gitaly.RefTransaction.VoteTransaction:input_type -> gitaly.VoteTransactionRequest
-	3, // 4: gitaly.RefTransaction.StopTransaction:input_type -> gitaly.StopTransactionRequest
-	2, // 5: gitaly.RefTransaction.VoteTransaction:output_type -> gitaly.VoteTransactionResponse
-	4, // 6: gitaly.RefTransaction.StopTransaction:output_type -> gitaly.StopTransactionResponse
-	5, // [5:7] is the sub-list for method output_type
-	3, // [3:5] is the sub-list for method input_type
-	3, // [3:3] is the sub-list for extension type_name
-	3, // [3:3] is the sub-list for extension extendee
-	0, // [0:3] is the sub-list for field type_name
+	6, // 0: gitaly.VoteTransactionRequest.repository:type_name -> gitaly.Repository
+	0, // 1: gitaly.VoteTransactionRequest.phase:type_name -> gitaly.VoteTransactionRequest.Phase
+	1, // 2: gitaly.VoteTransactionResponse.state:type_name -> gitaly.VoteTransactionResponse.TransactionState
+	6, // 3: gitaly.StopTransactionRequest.repository:type_name -> gitaly.Repository
+	2, // 4: gitaly.RefTransaction.VoteTransaction:input_type -> gitaly.VoteTransactionRequest
+	4, // 5: gitaly.RefTransaction.StopTransaction:input_type -> gitaly.StopTransactionRequest
+	3, // 6: gitaly.RefTransaction.VoteTransaction:output_type -> gitaly.VoteTransactionResponse
+	5, // 7: gitaly.RefTransaction.StopTransaction:output_type -> gitaly.StopTransactionResponse
+	6, // [6:8] is the sub-list for method output_type
+	4, // [4:6] is the sub-list for method input_type
+	4, // [4:4] is the sub-list for extension type_name
+	4, // [4:4] is the sub-list for extension extendee
+	0, // [0:4] is the sub-list for field type_name
 }
 
 func init() { file_transaction_proto_init() }
@@ -442,7 +518,7 @@ func file_transaction_proto_init() {
 		File: protoimpl.DescBuilder{
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: file_transaction_proto_rawDesc,
-			NumEnums:      1,
+			NumEnums:      2,
 			NumMessages:   4,
 			NumExtensions: 0,
 			NumServices:   1,
diff --git a/proto/transaction.proto b/proto/transaction.proto
index 745a764a5..3d3e48de5 100644
--- a/proto/transaction.proto
+++ b/proto/transaction.proto
@@ -26,6 +26,20 @@ service RefTransaction {
 }
 
 message VoteTransactionRequest {
+  enum Phase {
+    // UNKNOWN_PHASE is the unknown voting phase. This value has been the
+    // default because phases have been introduced. Eventually, using this
+    // phase will become unsupported.
+    UNKNOWN_PHASE = 0;
+    // PREPARED_PHASE is the prepratory phase. The data that is about to change
+    // is locked for concurrent modification, but changes have not yet been
+    // written to disk.
+    PREPARED_PHASE = 1;
+    // COMMITTED_PHASE is the committing phase. Data has been committed to disk
+    // and will be visible in all subsequent requests.
+    COMMITTED_PHASE  = 2;
+  };
+
   Repository repository = 1[(target_repository)=true];
   // ID of the transaction we're processing
   uint64 transaction_id = 2;
@@ -33,6 +47,8 @@ message VoteTransactionRequest {
   string node = 3;
   // SHA1 of the references that are to be updated
   bytes reference_updates_hash = 4;
+  // Phase is the voting phase.
+  Phase phase = 5;
 }
 
 message VoteTransactionResponse {
diff --git a/ruby/proto/gitaly/transaction_pb.rb b/ruby/proto/gitaly/transaction_pb.rb
index 59c7f5626..01a04bf3c 100644
--- a/ruby/proto/gitaly/transaction_pb.rb
+++ b/ruby/proto/gitaly/transaction_pb.rb
@@ -12,6 +12,12 @@ Google::Protobuf::DescriptorPool.generated_pool.build do
       optional :transaction_id, :uint64, 2
       optional :node, :string, 3
       optional :reference_updates_hash, :bytes, 4
+      optional :phase, :enum, 5, "gitaly.VoteTransactionRequest.Phase"
+    end
+    add_enum "gitaly.VoteTransactionRequest.Phase" do
+      value :UNKNOWN_PHASE, 0
+      value :PREPARED_PHASE, 1
+      value :COMMITTED_PHASE, 2
     end
     add_message "gitaly.VoteTransactionResponse" do
       optional :state, :enum, 1, "gitaly.VoteTransactionResponse.TransactionState"
@@ -32,6 +38,7 @@ end
 
 module Gitaly
   VoteTransactionRequest = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("gitaly.VoteTransactionRequest").msgclass
+  VoteTransactionRequest::Phase = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("gitaly.VoteTransactionRequest.Phase").enummodule
   VoteTransactionResponse = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("gitaly.VoteTransactionResponse").msgclass
   VoteTransactionResponse::TransactionState = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("gitaly.VoteTransactionResponse.TransactionState").enummodule
   StopTransactionRequest = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("gitaly.StopTransactionRequest").msgclass