Comment 4 for bug 1294760

So it looks like innobackupex is run with /tmp as an argument (default tmpdir?):

perl /usr/bin/innobackupex --defaults-file=/run/shm/galera0/mysql/etc/my.cnf --user=root --password=rootpass --socket=/dev/shm/galera0/mysql/var//mysqld.sock --galera-info --stream=tar /tmp

and tries to create schema directories right in /tmp. Perhaps specifying a different (and empty) tmpdir explicitly in my.cnf is a workaround.

Responsibility to create a dedicated empty directory inside tmpdir may belong with either innobackupex or SST script. Fixing SST is probably the right thing as it is responsible for the rest of the setup.