move log, ondisklog, missing from PG to PGLog

PG::log, PG::ondisklog, PG::missing are moved from PG to a new PGLog
class and are made protected data members. It is a preliminary step
before writing unit tests to cover the methods that have side effects
on these data members and define a clean PGLog API. It improves
encapsulation and does not change any of the logic already in
place.

Possible issues :

* an additional reference (PG->PGLog->IndexedLog instead of
  PG->IndexedLog for instance) is introduced : is it optimized ?

* rewriting log.log into pg_log.get_log().log affects the readability
  but should be optimized and have no impact on performances

The guidelines followed for this patch are:

* const access to the data members are preserved, no attempt is made
  to define accessors

* all non const methods are in PGLog, no access to non const methods of
  PGLog::log, PGLog::logondisk and PGLog::missing are provided

* when methods are moved from PG to PGLog the change to their
  implementation is restricted to the minimum.

* the PG::OndiskLog and PG::IndexedLog sub classes are moved
  to PGLog sub classes unmodified and remain public

A const version of the pg_log_t::find_entry method was added.

A const accessor is provided for PGLog::get_log, PGLog::get_missing,
PGLog::get_ondisklog but no non-const accessor.

Arguments are added to most of the methods moved from PG to PGLog so
that they can get access to PG data members such as info or log_oid.

The PGLog method are sorted according to the data member they modify.

//////////////////// missing ////////////////////

* The pg_missing_t::{got,have,need,add,rm} methods are wrapped as
  PGLog::missing_{got,have,need,add,rm}

//////////////////// log ////////////////////

* PGLog::get_tail, PGLog::get_head getters are created

* PGLog::set_tail, PGLog::set_head, PGLog::set_last_requested setters
  are created

* PGLog::index, PGLog::unindex, PGLog::add wrappers,
  PGLog::reset_recovery_pointers are created

* PGLog::clear_info_log replaces PG::clear_info_log

* PGLog::trim replaces PG::trim

//////////////////// log & missing ////////////////////

* PGLog::claim_log is created with code extracted from
  PG::RecoveryState::Stray::react.

* PGLog::split_into is created with code extracted from
  PG::split_into.

* PGLog::recover_got is created with code extracted from
  ReplicatedPG::recover_got.

* PGLog::activate_not_complete is created with code extracted
  from PG::active

* PGLog:proc_replica_log is created with code extracted from
  PG::proc_replica_log

* PGLog:write_log is created with code extracted from
  PG::write_log

* PGLog::merge_old_entry replaces PG::merge_old_entry
  The remove_snap argument is used to collect hobject_t

* PGLog::rewind_divergent_log replaces PG::rewind_divergent_log
  The remove_snap argument is used to collect hobject_t
  A new PG::rewind_divergent_log method is added to call
  remove_snap_mapped_object on each of the remove_snap
  elements

* PGLog::merge_log replaces PG::merge_log
  The remove_snap argument is used to collect hobject_t
  A new PG::merge_log method is added to call
  remove_snap_mapped_object on each of the remove_snap
  elements

* PGLog:write_log is created with code extracted from PG::write_log. A
  non-static version is created for convenience but is a simple
  wrapper.

* PGLog:read_log replaces PG::read_log. A non-static version is
  created for convenience but is a simple wrapper.

* PGLog:read_log_old replaces PG::read_log_old.

http://tracker.ceph.com/issues/5046 refs #5046

Signed-off-by: Loic Dachary <loic@dachary.org>

1 files changed, 7 insertions, 5 deletions

diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc
index 0ca3092372f..b6bdf2de409 100644
--- a/src/osd/OSD.cc
+++ b/src/osd/OSD.cc
@@ -1829,7 +1829,7 @@ void OSD::load_pgs()
     PG::RecoveryCtx rctx(0, 0, 0, 0, 0, 0);
     pg->handle_loaded(&rctx);
 
-    dout(10) << "load_pgs loaded " << *pg << " " << pg->log << dendl;
+    dout(10) << "load_pgs loaded " << *pg << " " << pg->pg_log.get_log() << dendl;
     pg->unlock();
   }
   dout(10) << "load_pgs done" << dendl;
@@ -3034,7 +3034,7 @@ void OSD::RemoveWQ::_process(pair<PGRef, DeletingStateRef> item)
     return;
 
   ObjectStore::Transaction *t = new ObjectStore::Transaction;
-  PG::clear_info_log(
+  PGLog::clear_info_log(
     pg->info.pgid,
     OSD::make_infos_oid(),
     pg->log_oid,
@@ -3645,8 +3645,10 @@ void OSD::do_command(Connection *con, tid_t tid, vector<string>& cmd, bufferlist
 	pg->lock();
 
 	fout << *pg << std::endl;
-	std::map<hobject_t, pg_missing_t::item>::iterator mend = pg->missing.missing.end();
-	std::map<hobject_t, pg_missing_t::item>::iterator mi = pg->missing.missing.begin();
+	std::map<hobject_t, pg_missing_t::item>::const_iterator mend =
+	  pg->pg_log.get_missing().missing.end();
+	std::map<hobject_t, pg_missing_t::item>::const_iterator mi =
+	  pg->pg_log.get_missing().missing.begin();
 	for (; mi != mend; ++mi) {
 	  fout << mi->first << " -> " << mi->second << std::endl;
 	  map<hobject_t, set<int> >::const_iterator mli =
@@ -5756,7 +5758,7 @@ void OSD::handle_pg_trim(OpRequestRef op)
     } else {
       // primary is instructing us to trim
       ObjectStore::Transaction *t = new ObjectStore::Transaction;
-      pg->trim(*t, m->trim_to);
+      pg->pg_log.trim(*t, m->trim_to, pg->info, pg->log_oid);
       pg->dirty_info = true;
       pg->write_if_dirty(*t);
       int tr = store->queue_transaction(pg->osr.get(), t,