ReplicatedPG: reset new_obs and new_snapset in execute_ctx

This way, if execute_ctx is rerun on the same OpContext, we
won't erroneously reuse a stale snapset/object_info.

Signed-off-by: Samuel Just <sam.just@inktank.com>
OpRequest: move method implementations into cc

I need to remove the osd_types.h include.

Signed-off-by: Samuel Just <sam.just@inktank.com>
osd_types,OpRequest: move osd_req_id into OpRequest

This way I can have OpRequest included from osd_types.h.

Signed-off-by: Samuel Just <sam.just@inktank.com>
ReplicatedPG,osd_types: move rw tracking from its own map to ObjectContext

We also modify recovering to hold a reference to the recovering obc
in order to ensure that our backfill_read_lock doesn't outlive the
obc.

ReplicatedPG::op_applied no longer clears repop->obc since we need
it to live until the op is finally cleaned up.  This is fine since
repop->obc is now an ObjectContextRef and can clean itself up.

Signed-off-by: Samuel Just <sam.just@inktank.com>
ReplicatedBackend: fix failed push error output

Signed-off-by: Samuel Just <sam.just@inktank.com>
ReplicatedPG: have make_writeable adjust backfill_pos

If we are writing to backfill_pos and create a clone, we end
up failing to send the transaction creating the clone to the
backfill peer.  This is fine as long as we end up backfilling
the clone.  To that end, we simply add the clone to
backfill_info and adjust backfill_pos accordingly.  This is less
brittle than the waiting_for_backfill_pos mechanism since it
works even if we wait between that check and issuing the repop,
which can happen for copy_from.

Signed-off-by: Samuel Just <sam.just@inktank.com>
PG,ReplicatedPG: remove the waiting_for_backfill_peer mechanism

See previous patch.

Signed-off-by: Samuel Just <sam.just@inktank.com>
PG: call on_flushed on FlushEvt

Signed-off-by: Samuel Just <sam.just@inktank.com>
ReplicatedPG: improved on_flushed error output

Signed-off-by: Samuel Just <sam.just@inktank.com>
ReplicatedPG: put repops even in TrimObjects

Signed-off-by: Samuel Just <sam.just@inktank.com>
ReplicatedBackend: don't hold ObjectContexts in pull completion callback

We need flushing the sequencer to ensure that all Contexts which hold
ObjectContextRefs have been run or deleted.
C_ReplicatedBackend_OnPullComplete, however, gets queued in a second
work queue in order to avoid performing expensive push related reads
in the FileStore finisher.

Rather than keep the objects contexts around, we instead put off
removing the object from the pulling map until the call back
fires and read the object context out of the pulling map.  This
way the ObjectContextRef will be cleaned up along with the rest
of the pulling map in on_change.

Signed-off-by: Samuel Just <sam.just@inktank.com>