diff --git a/libs/ui/BufferHubBuffer.cpp b/libs/ui/BufferHubBuffer.cpp
index e747ee1..3816c1b 100644
--- a/libs/ui/BufferHubBuffer.cpp
+++ b/libs/ui/BufferHubBuffer.cpp
@@ -61,6 +61,16 @@
 // to use Binder.
 static constexpr char kBufferHubClientPath[] = "system/buffer_hub/client";
 
+using dvr::BufferHubDefs::AnyClientAcquired;
+using dvr::BufferHubDefs::AnyClientGained;
+using dvr::BufferHubDefs::AnyClientPosted;
+using dvr::BufferHubDefs::IsClientAcquired;
+using dvr::BufferHubDefs::IsClientGained;
+using dvr::BufferHubDefs::IsClientPosted;
+using dvr::BufferHubDefs::IsClientReleased;
+using dvr::BufferHubDefs::kHighBitsMask;
+using dvr::BufferHubDefs::kMetadataHeaderSize;
+
 } // namespace
 
 BufferHubClient::BufferHubClient() : Client(ClientChannelFactory::Create(kBufferHubClientPath)) {}
@@ -71,7 +81,7 @@
 BufferHubClient::~BufferHubClient() {}
 
 bool BufferHubClient::IsValid() const {
-  return IsConnected() && GetChannelHandle().valid();
+    return IsConnected() && GetChannelHandle().valid();
 }
 
 LocalChannelHandle BufferHubClient::TakeChannelHandle() {
@@ -151,11 +161,17 @@
     }
 
     size_t metadataSize = static_cast<size_t>(bufferTraits.metadata_size());
-    if (metadataSize < dvr::BufferHubDefs::kMetadataHeaderSize) {
+    if (metadataSize < kMetadataHeaderSize) {
         ALOGE("BufferHubBuffer::ImportGraphicBuffer: metadata too small: %zu", metadataSize);
         return -EINVAL;
     }
 
+    // Populate shortcuts to the atomics in metadata.
+    auto metadata_header = mMetadata.metadata_header();
+    buffer_state_ = &metadata_header->buffer_state;
+    fence_state_ = &metadata_header->fence_state;
+    active_clients_bit_mask_ = &metadata_header->active_clients_bit_mask;
+
     // Import the buffer: We only need to hold on the native_handle_t here so that
     // GraphicBuffer instance can be created in future.
     mBufferHandle = bufferTraits.take_buffer_handle();
@@ -176,7 +192,93 @@
 
     // TODO(b/112012161) Set up shared fences.
     ALOGD("BufferHubBuffer::ImportGraphicBuffer: id=%d, buffer_state=%" PRIx64 ".", id(),
-          mMetadata.metadata_header()->buffer_state.load(std::memory_order_acquire));
+          buffer_state_->load(std::memory_order_acquire));
+    return 0;
+}
+
+int BufferHubBuffer::Gain() {
+    uint64_t current_buffer_state = buffer_state_->load(std::memory_order_acquire);
+    if (IsClientGained(current_buffer_state, mClientStateMask)) {
+        ALOGV("%s: Buffer is already gained by this client %" PRIx64 ".", __FUNCTION__,
+              mClientStateMask);
+        return 0;
+    }
+    do {
+        if (AnyClientGained(current_buffer_state & (~mClientStateMask)) ||
+            AnyClientAcquired(current_buffer_state)) {
+            ALOGE("%s: Buffer is in use, id=%d mClientStateMask=%" PRIx64 " state=%" PRIx64 ".",
+                  __FUNCTION__, mId, mClientStateMask, current_buffer_state);
+            return -EBUSY;
+        }
+        // Change the buffer state to gained state, whose value happens to be the same as
+        // mClientStateMask.
+    } while (!buffer_state_->compare_exchange_weak(current_buffer_state, mClientStateMask,
+                                                   std::memory_order_acq_rel,
+                                                   std::memory_order_acquire));
+    // TODO(b/119837586): Update fence state and return GPU fence.
+    return 0;
+}
+
+int BufferHubBuffer::Post() {
+    uint64_t current_buffer_state = buffer_state_->load(std::memory_order_acquire);
+    uint64_t current_active_clients_bit_mask = 0ULL;
+    uint64_t updated_buffer_state = 0ULL;
+    do {
+        if (!IsClientGained(current_buffer_state, mClientStateMask)) {
+            ALOGE("%s: Cannot post a buffer that is not gained by this client. buffer_id=%d "
+                  "mClientStateMask=%" PRIx64 " state=%" PRIx64 ".",
+                  __FUNCTION__, mId, mClientStateMask, current_buffer_state);
+            return -EBUSY;
+        }
+        // Set the producer client buffer state to released, other clients' buffer state to posted.
+        current_active_clients_bit_mask = active_clients_bit_mask_->load(std::memory_order_acquire);
+        updated_buffer_state =
+                current_active_clients_bit_mask & (~mClientStateMask) & kHighBitsMask;
+    } while (!buffer_state_->compare_exchange_weak(current_buffer_state, updated_buffer_state,
+                                                   std::memory_order_acq_rel,
+                                                   std::memory_order_acquire));
+    // TODO(b/119837586): Update fence state and return GPU fence if needed.
+    return 0;
+}
+
+int BufferHubBuffer::Acquire() {
+    uint64_t current_buffer_state = buffer_state_->load(std::memory_order_acquire);
+    if (IsClientAcquired(current_buffer_state, mClientStateMask)) {
+        ALOGV("%s: Buffer is already acquired by this client %" PRIx64 ".", __FUNCTION__,
+              mClientStateMask);
+        return 0;
+    }
+    uint64_t updated_buffer_state = 0ULL;
+    do {
+        if (!IsClientPosted(current_buffer_state, mClientStateMask)) {
+            ALOGE("%s: Cannot acquire a buffer that is not in posted state. buffer_id=%d "
+                  "mClientStateMask=%" PRIx64 " state=%" PRIx64 ".",
+                  __FUNCTION__, mId, mClientStateMask, current_buffer_state);
+            return -EBUSY;
+        }
+        // Change the buffer state for this consumer from posted to acquired.
+        updated_buffer_state = current_buffer_state ^ mClientStateMask;
+    } while (!buffer_state_->compare_exchange_weak(current_buffer_state, updated_buffer_state,
+                                                   std::memory_order_acq_rel,
+                                                   std::memory_order_acquire));
+    // TODO(b/119837586): Update fence state and return GPU fence.
+    return 0;
+}
+
+int BufferHubBuffer::Release() {
+    uint64_t current_buffer_state = buffer_state_->load(std::memory_order_acquire);
+    if (IsClientReleased(current_buffer_state, mClientStateMask)) {
+        ALOGV("%s: Buffer is already released by this client %" PRIx64 ".", __FUNCTION__,
+              mClientStateMask);
+        return 0;
+    }
+    uint64_t updated_buffer_state = 0ULL;
+    do {
+        updated_buffer_state = current_buffer_state & (~mClientStateMask);
+    } while (!buffer_state_->compare_exchange_weak(current_buffer_state, updated_buffer_state,
+                                                   std::memory_order_acq_rel,
+                                                   std::memory_order_acquire));
+    // TODO(b/119837586): Update fence state and return GPU fence if needed.
     return 0;
 }
 
diff --git a/libs/ui/include/ui/BufferHubBuffer.h b/libs/ui/include/ui/BufferHubBuffer.h
index 6850b43..03d10e7 100644
--- a/libs/ui/include/ui/BufferHubBuffer.h
+++ b/libs/ui/include/ui/BufferHubBuffer.h
@@ -103,6 +103,27 @@
     // to read from and/or write into.
     bool IsValid() const { return mBufferHandle.IsValid(); }
 
+    // Gains the buffer for exclusive write permission. Read permission is implied once a buffer is
+    // gained.
+    // The buffer can be gained as long as there is no other client in acquired or gained state.
+    int Gain();
+
+    // Posts the gained buffer for other buffer clients to use the buffer.
+    // The buffer can be posted iff the buffer state for this client is gained.
+    // After posting the buffer, this client is put to released state and does not have access to
+    // the buffer for this cycle of the usage of the buffer.
+    int Post();
+
+    // Acquires the buffer for shared read permission.
+    // The buffer can be acquired iff the buffer state for this client is posted.
+    int Acquire();
+
+    // Releases the buffer.
+    // The buffer can be released from any buffer state.
+    // After releasing the buffer, this client no longer have any permissions to the buffer for the
+    // current cycle of the usage of the buffer.
+    int Release();
+
     // Returns the event mask for all the events that are pending on this buffer (see sys/poll.h for
     // all possible bits).
     pdx::Status<int> GetEventMask(int events) {
@@ -130,6 +151,9 @@
 
     // Global id for the buffer that is consistent across processes.
     int mId = -1;
+
+    // Client state mask of this BufferHubBuffer object. It is unique amoung all
+    // clients/users of the buffer.
     uint64_t mClientStateMask = 0;
 
     // Stores ground truth of the buffer.
@@ -141,6 +165,10 @@
     // An ashmem-based metadata object. The same shared memory are mapped to the
     // bufferhubd daemon and all buffer clients.
     BufferHubMetadata mMetadata;
+    // Shortcuts to the atomics inside the header of mMetadata.
+    std::atomic<uint64_t>* buffer_state_{nullptr};
+    std::atomic<uint64_t>* fence_state_{nullptr};
+    std::atomic<uint64_t>* active_clients_bit_mask_{nullptr};
 
     // PDX backend.
     BufferHubClient mClient;
diff --git a/libs/ui/tests/BufferHubBuffer_test.cpp b/libs/ui/tests/BufferHubBuffer_test.cpp
index 6c7d06b..e33acf6 100644
--- a/libs/ui/tests/BufferHubBuffer_test.cpp
+++ b/libs/ui/tests/BufferHubBuffer_test.cpp
@@ -36,7 +36,14 @@
 const int kUsage = 0;
 const size_t kUserMetadataSize = 0;
 
+using dvr::BufferHubDefs::AnyClientAcquired;
+using dvr::BufferHubDefs::AnyClientGained;
+using dvr::BufferHubDefs::AnyClientPosted;
 using dvr::BufferHubDefs::IsBufferReleased;
+using dvr::BufferHubDefs::IsClientAcquired;
+using dvr::BufferHubDefs::IsClientGained;
+using dvr::BufferHubDefs::IsClientPosted;
+using dvr::BufferHubDefs::IsClientReleased;
 using dvr::BufferHubDefs::kFirstClientBitMask;
 using dvr::BufferHubDefs::kMetadataHeaderSize;
 using frameworks::bufferhub::V1_0::BufferHubStatus;
@@ -48,9 +55,40 @@
 using pdx::LocalChannelHandle;
 
 class BufferHubBufferTest : public ::testing::Test {
+protected:
     void SetUp() override { android::hardware::ProcessState::self()->startThreadPool(); }
 };
 
+class BufferHubBufferStateTransitionTest : public BufferHubBufferTest {
+protected:
+    void SetUp() override {
+        BufferHubBufferTest::SetUp();
+        CreateTwoClientsOfABuffer();
+    }
+
+    std::unique_ptr<BufferHubBuffer> b1;
+    uint64_t b1ClientMask = 0ULL;
+    std::unique_ptr<BufferHubBuffer> b2;
+    uint64_t b2ClientMask = 0ULL;
+
+private:
+    // Creates b1 and b2 as the clients of the same buffer for testing.
+    void CreateTwoClientsOfABuffer();
+};
+
+void BufferHubBufferStateTransitionTest::CreateTwoClientsOfABuffer() {
+    b1 = BufferHubBuffer::Create(kWidth, kHeight, kLayerCount, kFormat, kUsage, kUserMetadataSize);
+    b1ClientMask = b1->client_state_mask();
+    ASSERT_NE(b1ClientMask, 0ULL);
+    auto statusOrHandle = b1->Duplicate();
+    ASSERT_TRUE(statusOrHandle);
+    LocalChannelHandle h2 = statusOrHandle.take();
+    b2 = BufferHubBuffer::Import(std::move(h2));
+    b2ClientMask = b2->client_state_mask();
+    ASSERT_NE(b2ClientMask, 0ULL);
+    ASSERT_NE(b2ClientMask, b1ClientMask);
+}
+
 TEST_F(BufferHubBufferTest, CreateBufferHubBufferFails) {
     // Buffer Creation will fail: BLOB format requires height to be 1.
     auto b1 = BufferHubBuffer::Create(kWidth, /*height=*/2, kLayerCount,
@@ -315,5 +353,180 @@
     EXPECT_EQ(nullptr, client2.get());
 }
 
+TEST_F(BufferHubBufferStateTransitionTest, GainBuffer_fromReleasedState) {
+    ASSERT_TRUE(IsBufferReleased(b1->buffer_state()));
+
+    // Successful gaining the buffer should change the buffer state bit of b1 to
+    // gained state, other client state bits to released state.
+    EXPECT_EQ(b1->Gain(), 0);
+    EXPECT_TRUE(IsClientGained(b1->buffer_state(), b1ClientMask));
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, GainBuffer_fromGainedState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    auto current_buffer_state = b1->buffer_state();
+    ASSERT_TRUE(IsClientGained(current_buffer_state, b1ClientMask));
+
+    // Gaining from gained state by the same client should not return error.
+    EXPECT_EQ(b1->Gain(), 0);
+
+    // Gaining from gained state by another client should return error.
+    EXPECT_EQ(b2->Gain(), -EBUSY);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, GainBuffer_fromAcquiredState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_EQ(b1->Post(), 0);
+    ASSERT_EQ(b2->Acquire(), 0);
+    ASSERT_TRUE(AnyClientAcquired(b1->buffer_state()));
+
+    // Gaining from acquired state should fail.
+    EXPECT_EQ(b1->Gain(), -EBUSY);
+    EXPECT_EQ(b2->Gain(), -EBUSY);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, GainBuffer_fromOtherClientInPostedState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_EQ(b1->Post(), 0);
+    ASSERT_TRUE(AnyClientPosted(b1->buffer_state()));
+
+    // Gaining a buffer who has other posted client should succeed.
+    EXPECT_EQ(b1->Gain(), 0);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, GainBuffer_fromSelfInPostedState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_EQ(b1->Post(), 0);
+    ASSERT_TRUE(AnyClientPosted(b1->buffer_state()));
+
+    // A posted client should be able to gain the buffer when there is no other clients in
+    // acquired state.
+    EXPECT_EQ(b2->Gain(), 0);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, PostBuffer_fromOtherInGainedState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_TRUE(IsClientGained(b1->buffer_state(), b1ClientMask));
+
+    EXPECT_EQ(b2->Post(), -EBUSY);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, PostBuffer_fromSelfInGainedState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_TRUE(IsClientGained(b1->buffer_state(), b1ClientMask));
+
+    EXPECT_EQ(b1->Post(), 0);
+    auto current_buffer_state = b1->buffer_state();
+    EXPECT_TRUE(IsClientReleased(current_buffer_state, b1ClientMask));
+    EXPECT_TRUE(IsClientPosted(current_buffer_state, b2ClientMask));
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, PostBuffer_fromPostedState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_EQ(b1->Post(), 0);
+    ASSERT_TRUE(AnyClientPosted(b1->buffer_state()));
+
+    // Post from posted state should fail.
+    EXPECT_EQ(b1->Post(), -EBUSY);
+    EXPECT_EQ(b2->Post(), -EBUSY);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, PostBuffer_fromAcquiredState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_EQ(b1->Post(), 0);
+    ASSERT_EQ(b2->Acquire(), 0);
+    ASSERT_TRUE(AnyClientAcquired(b1->buffer_state()));
+
+    // Posting from acquired state should fail.
+    EXPECT_EQ(b1->Post(), -EBUSY);
+    EXPECT_EQ(b2->Post(), -EBUSY);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, PostBuffer_fromReleasedState) {
+    ASSERT_TRUE(IsBufferReleased(b1->buffer_state()));
+
+    // Posting from released state should fail.
+    EXPECT_EQ(b1->Post(), -EBUSY);
+    EXPECT_EQ(b2->Post(), -EBUSY);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, AcquireBuffer_fromSelfInPostedState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_EQ(b1->Post(), 0);
+    ASSERT_TRUE(IsClientPosted(b1->buffer_state(), b2ClientMask));
+
+    // Acquire from posted state should pass.
+    EXPECT_EQ(b2->Acquire(), 0);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, AcquireBuffer_fromOtherInPostedState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_EQ(b1->Post(), 0);
+    ASSERT_TRUE(IsClientPosted(b1->buffer_state(), b2ClientMask));
+
+    // Acquire from released state should fail, although there are other clients
+    // in posted state.
+    EXPECT_EQ(b1->Acquire(), -EBUSY);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, AcquireBuffer_fromSelfInAcquiredState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_EQ(b1->Post(), 0);
+    ASSERT_EQ(b2->Acquire(), 0);
+    auto current_buffer_state = b1->buffer_state();
+    ASSERT_TRUE(IsClientAcquired(current_buffer_state, b2ClientMask));
+
+    // Acquiring from acquired state by the same client should not error out.
+    EXPECT_EQ(b2->Acquire(), 0);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, AcquireBuffer_fromReleasedState) {
+    ASSERT_TRUE(IsBufferReleased(b1->buffer_state()));
+
+    // Acquiring form released state should fail.
+    EXPECT_EQ(b1->Acquire(), -EBUSY);
+    EXPECT_EQ(b2->Acquire(), -EBUSY);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, AcquireBuffer_fromGainedState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_TRUE(AnyClientGained(b1->buffer_state()));
+
+    // Acquiring from gained state should fail.
+    EXPECT_EQ(b1->Acquire(), -EBUSY);
+    EXPECT_EQ(b2->Acquire(), -EBUSY);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, ReleaseBuffer_fromSelfInReleasedState) {
+    ASSERT_TRUE(IsBufferReleased(b1->buffer_state()));
+
+    EXPECT_EQ(b1->Release(), 0);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, ReleaseBuffer_fromSelfInGainedState) {
+    ASSERT_TRUE(IsBufferReleased(b1->buffer_state()));
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_TRUE(AnyClientGained(b1->buffer_state()));
+
+    EXPECT_EQ(b1->Release(), 0);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, ReleaseBuffer_fromSelfInPostedState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_EQ(b1->Post(), 0);
+    ASSERT_TRUE(AnyClientPosted(b1->buffer_state()));
+
+    EXPECT_EQ(b2->Release(), 0);
+}
+
+TEST_F(BufferHubBufferStateTransitionTest, ReleaseBuffer_fromSelfInAcquiredState) {
+    ASSERT_EQ(b1->Gain(), 0);
+    ASSERT_EQ(b1->Post(), 0);
+    ASSERT_EQ(b2->Acquire(), 0);
+    ASSERT_TRUE(AnyClientAcquired(b1->buffer_state()));
+
+    EXPECT_EQ(b2->Release(), 0);
+}
+
 } // namespace
 } // namespace android