Before this change we sorted transfers in the stats list solely on
time started. However if --check-first was in use then lots of
transfers could be started in the same millisecond. Because Windows
time resolution is only 1mS this caused the entries to sort equal and
bounce around in the list.
This change fixes the sort so that if the time is equal it uses the
name which should stabilize the order.
Fixes#4599
The deadlock was caused in transfermap.go by calling mu.RLock() in one
function then calling it again in a sub function. Normally this is
fine, however this leaves a window where mu.Lock() can be called. When
mu.Lock() is called it doesn't allow the second mu.RLock() and
deadlocks.
Thead 1 Thread 2
String():mu.RLock()
del():mu.Lock()
sortedSlice():mu.RLock() - DEADLOCK
Lesson learnt: don't try using locks recursively ever!
This patch fixes the problem by removing the second mu.RLock(). This
was done by factoring the code that was calling it into the
transfermap.go file so all the locking can be seen at once which was
ultimately the cause of the problem - the code which used the locks
was too far away from the rest of the code using the lock.
This problem was introduced in:
bfa5715017 fs/accounting: sort transfers by start time
Which hasn't been released in a stable version yet
