Comment 2 for bug 1384062

I can reproduce this on Wily with

# apt-cache policy ceph
ceph:
  Installed: 0.94.5-0ubuntu0.15.10.1
  Candidate: 0.94.5-0ubuntu0.15.10.1
  Version table:
 *** 0.94.5-0ubuntu0.15.10.1 0
        500 http://eu.archive.ubuntu.com/ubuntu/ wily-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     0.94.3-0ubuntu2 0
        500 http://eu.archive.ubuntu.com/ubuntu/ wily/main amd64 Packages

when I configure two OSDs both with their journal partition on a third disk. Running os-prober makes the second OSD fail with

     0> 2016-02-16 15:15:17.604773 7fe2c7ec8700 -1 os/FileJournal.cc: In function 'void FileJournal::write_finish_thread_entry()' thread 7fe2c7ec8700 time 2016-02-16 15:15:17.603014
os/FileJournal.cc: 1426: FAILED assert(0 == "unexpected aio error")

 ceph version 0.94.5 (9764da52395923e0b32908d83a9f7304401fee43)
 1: (ceph::__ceph_assert_fail(char const*, char const*, int, char const*)+0x80) [0x556db4ce44f0]
 2: (FileJournal::write_finish_thread_entry()+0x775) [0x556db4bb5925]
 3: (FileJournal::WriteFinisher::entry()+0xd) [0x556db4a990ed]
 4: (()+0x76aa) [0x7fe2d32656aa]
 5: (clone()+0x6d) [0x7fe2d173ceed]
 NOTE: a copy of the executable, or `objdump -rdS <executable>` is needed to interpret this.

which seems to indicate that os-prober is doing unsafe things to the journal partitions.