483     BufferStorage *copyDest = nullptr;  in copySubData()  local
484     ANGLE_TRY(getLatestBufferStorage(context, &copyDest));  in copySubData()
486     if (!copyDest)  in copySubData()
488         ANGLE_TRY(getStagingStorage(context, &copyDest));  in copySubData()
499     ASSERT(copySource && copyDest);  in copySubData()
502     if (!copyDest->isGPUAccessible() && !copySource->isCPUAccessible(GL_MAP_READ_BIT))  in copySubData()
506     else if (!copySource->isGPUAccessible() && !copyDest->isCPUAccessible(GL_MAP_WRITE_BIT))  in copySubData()
508         ANGLE_TRY(getStagingStorage(context, &copyDest));  in copySubData()
514     if (copySource == copyDest)  in copySubData()
528     ANGLE_TRY(copyDest->copyFromStorage(context, copySource, sourceOffset, size, destOffset,  in copySubData()
530     onStorageUpdate(copyDest);  in copySubData()