Fix 6181/6182 (#6183)

* set larger buf size for LogBuffer

* jump to next day when no more entry found

* Update weed/filer/filer_notify_read.go

---------

Co-authored-by: Chris Lu <chrislusf@users.noreply.github.com>

weed/util/time.go

@@ -0,0 +1,13 @@
+package util
+
+import (
+	"time"
+)
+
+func GetNextDayTsNano(curTs int64) int64 {
+	curTime := time.Unix(0, curTs)
+	nextDay := curTime.AddDate(0, 0, 1).Truncate(24 * time.Hour)
+	nextDayNano := nextDay.UnixNano()
+
+	return nextDayNano
+}