tree 58888be00ebc7840ace82f2a6c1bdb6ff9007d5e
parent 3850cbac5c2b813cdcf27be18cea9492b0bc0531
author Robin Thellend <rthellend@google.com> 1466469392 -0700
committer Robin Thellend <rthellend@google.com> 1466473250 +0000

services/mounttable/btmtd: Fix bug with concurrent createChild

When createChild() is called concurrently, it is possible to leave an
incorrect reference in the parent, e.g.

createChild1 --> insert child with ts1 in parent
 createChild2 --> insert child with ts2 in parent

createChild1 --> Create child row with ts1
 createChild2 --> Create child row wth ts2 (Fails, already exists)

OR,

createChild1 --> insert child with ts1 in parent
 createChild2 --> insert child with ts2 in parent

 createChild2 --> Create child row wth ts2
createChild1 --> Create child row with ts1 (Fails, already exists)

When createChild1 or createChild2 fails, the reference in the parent
for ts1 or ts2 was left behind. The fix is to delete that reference when
the row creation fails.

https://github.com/vanadium/build/issues/88

Change-Id: I9947ef2459550636ce0bc7ec3f8c1766f789bbec