Update writemarker lock function (#931)

Co-authored-by: peterlimg <54137706+peterlimg@users.noreply.github.com>

Author: lpoli

code/go/0chain.net/blobbercore/writemarker/mutex.go

@@ -32,7 +32,10 @@ type Mutex struct {
 ML *common.MapLocker
 }
 
-// Lock
+// Lock will create/update lock in postgres.
+// If no lock exists for an allocation then new lock is created.
+// If lock exists and is of same connection ID then lock's createdAt is updated
+// If lock exists and is of other connection ID then `pending` response is sent.
 func (m *Mutex) Lock(ctx context.Context, allocationID, connectionID string, requestTime *time.Time) (*LockResult, error) {
 if allocationID == "" {
 return nil, errors.Throw(constants.ErrInvalidParameter, "allocationID")
@@ -77,48 +80,30 @@ func (m *Mutex) Lock(ctx context.Context, allocationID, connectionID string, req
 Status: LockStatusOK,
 CreatedAt: lock.CreatedAt.Unix(),
 }, nil
-
 }
 
 //native postgres error
 return nil, errors.ThrowLog(err.Error(), common.ErrBadDataStore)
-
 }
 
-timeout := lock.CreatedAt.Add(config.Configuration.WriteMarkerLockTimeout)
-
-// locked, but it is timeout
-if now.After(timeout) {
-
-lock.ConnectionID = connectionID
-lock.CreatedAt = *requestTime
-
-err = db.Table(TableNameWriteLock).Where("allocation_id=?", allocationID).Save(&lock).Error
-if err != nil {
-return nil, errors.ThrowLog(err.Error(), common.ErrBadDataStore)
-}
-
+if lock.ConnectionID != connectionID {
+// pending
 return &LockResult{
-Status: LockStatusOK,
+Status: LockStatusPending,
 CreatedAt: lock.CreatedAt.Unix(),
 }, nil
-
 }
 
-//try lock by same session, return old lock directly
-if lock.ConnectionID == connectionID && lock.CreatedAt.Equal(*requestTime) {
-return &LockResult{
-Status: LockStatusOK,
-CreatedAt: lock.CreatedAt.Unix(),
-}, nil
+lock.CreatedAt = *requestTime
+err = db.Table(TableNameWriteLock).Where("allocation_id=?", allocationID).Save(&lock).Error
+if err != nil {
+return nil, errors.ThrowLog(err.Error(), common.ErrBadDataStore)
 }
 
-// pending
 return &LockResult{
-Status: LockStatusPending,
+Status: LockStatusOK,
 CreatedAt: lock.CreatedAt.Unix(),
 }, nil
-
 }
 
 func (*Mutex) Unlock(ctx context.Context, allocationID string, connectionID string) error {