Merge remote-tracking branch 'ac/wip-lttng' into wip-lttng

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
tracing: instrument filestore

This adds objectstore tracepoints for the filestore. It'd be nice to add
these to the objectstore interface some how so we can get all
implementations for free, but that might just be a bit difficult
especially since each impl will apply transactions in a differnet way.

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
lttng: Add more tracing to librbd

Includes:
- aio_complete
- aio_discard
- aio_flush
- aio_get_return_value
- aio_is_complete
- aio_read
- aio_wait_for_complete
- aio_write
- copy
- discard
- flush
- invalidate_cache
- rename
- resize
- Add ImageCtx pointer to trace points
- Add snap_name and readonly flag to trace point open_image_enter

Signed-off-by: Adam Crume <adamcrume@gmail.com>
lttng: Add rbd-replay

Signed-off-by: Adam Crume <adamcrume@gmail.com>