ceph_test_rados_api_*: expose nspace

Signed-off-by: Sage Weil <sage@redhat.com>
ceph_test_rados_api_io: add read timeout test

Verify we don't receive data after a timeout.

Based on reproducer for #9362 written by
Matthias Kiefer <matthias.kiefer@1und1.de>.

Signed-off-by: Sage Weil <sage@redhat.com>
osdc/Objecter: revoke rx_buffer on op_cancel

If we cancel a read, revoke the rx buffers to avoid a use-after-free and/or
other undefined badness by using user buffers that may no longer be
present.

Fixes: #9362
Backport: firefly, dumpling
Reported-by: Matthias Kiefer <matthias.kiefer@1und1.de>
Signed-off-by: Sage Weil <sage@redhat.com>
Merge pull request #2427 from ceph/wip-9362

librados: do not write to user buffer after timeout

Reviewed-by: Greg Farnum <greg@inktank.com>