mds: don't take mds_lock when doing journal operations

Now journaler and objecter have internal locks to protect themself, there is
no need to take the mds_lock before using journaler and objecter.

Signed-off-by: Yan, Zheng <zyan@redhat.com>

diff --git a/src/mds/MDLog.cc b/src/mds/MDLog.cc
index 473b7ce32b635b7d0eddb3fb0fedf5c36231364a..373ded4e183b991428fb19480f606acedf79a555 100644 (file)
--- a/src/mds/MDLog.cc
+++ b/src/mds/MDLog.cc
@@ -341,8 +341,6 @@ void MDLog::_submit_thread()
       bufferlist bl;
       le->encode_with_header(bl);
 
-      mds->mds_lock.Lock();
-
       uint64_t write_pos = journaler->get_write_pos();
 
       le->set_start_off(write_pos);
@@ -361,19 +359,15 @@ void MDLog::_submit_thread()
       if (data.flush)
        journaler->flush();
 
-      mds->mds_lock.Unlock();
-
       if (logger)
        logger->set(l_mdl_wrpos, ls->end);
 
       delete le;
     } else {
-      mds->mds_lock.Lock();
       if (data.fin)
        journaler->wait_for_flush(new C_IO_Wrapper(mds, data.fin));
       if (data.flush)
        journaler->flush();
-      mds->mds_lock.Unlock();
     }
 
     submit_mutex.Lock();
@@ -739,9 +733,7 @@ void MDLog::_recovery_thread(MDSInternalContextBase *completion)
     if (mds->is_standby_replay()) {
       dout(1) << "Journal " << jp.front << " is being rewritten, "
         << "cannot replay in standby until an active MDS completes rewrite" << dendl;
-      mds->mds_lock.Lock();
       completion->complete(-EAGAIN);
-      mds->mds_lock.Unlock();
       return;
     }
     dout(1) << "Erasing journal " << jp.back << dendl;
@@ -750,19 +742,15 @@ void MDLog::_recovery_thread(MDSInternalContextBase *completion)
         mds->objecter, logger, l_mdl_jlat, &mds->timer, &mds->finisher);
 
     // Read all about this journal (header + extents)
-    mds->mds_lock.Lock();
     C_SaferCond recover_wait;
     back.recover(&recover_wait);
-    mds->mds_lock.Unlock();
     int recovery_result = recover_wait.wait();
 
     // Journaler.recover succeeds if no journal objects are present: an error
     // means something worse like a corrupt header, which we can't handle here.
     assert(recovery_result == 0);
     // We could read journal, so we can erase it.
-    mds->mds_lock.Lock();
     back.erase(&erase_waiter);
-    mds->mds_lock.Unlock();
     int erase_result = erase_waiter.wait();
 
     // If we are successful, or find no data, we can update the JournalPointer to
@@ -782,9 +770,7 @@ void MDLog::_recovery_thread(MDSInternalContextBase *completion)
   Journaler *front_journal = new Journaler(jp.front, mds->mdsmap->get_metadata_pool(),
       CEPH_FS_ONDISK_MAGIC, mds->objecter, logger, l_mdl_jlat, &mds->timer, &mds->finisher);
   C_SaferCond recover_wait;
-  mds->mds_lock.Lock();
   front_journal->recover(&recover_wait);
-  mds->mds_lock.Unlock();
   dout(4) << "Waiting for journal " << jp.front << " to recover..." << dendl;
   int recovery_result = recover_wait.wait();
   dout(4) << "Journal " << jp.front << " recovered." << dendl;
@@ -857,9 +843,7 @@ void MDLog::_reformat_journal(JournalPointer const &jp_in, Journaler *old_journa
 
   /* Write the new journal header to RADOS */
   C_SaferCond write_head_wait;
-  mds->mds_lock.Lock();
   new_journal->write_head(&write_head_wait);
-  mds->mds_lock.Unlock();
   write_head_wait.wait();
 
   // Read in the old journal, and whenever we have readable events,
@@ -870,7 +854,6 @@ void MDLog::_reformat_journal(JournalPointer const &jp_in, Journaler *old_journa
   // e.g. between checking readable and doing wait_for_readable so that journaler
   // state doesn't change in between.
   uint32_t events_transcribed = 0;
-  mds->mds_lock.Lock();
   while (1) {
     while (!old_journal->is_readable() &&
           old_journal->get_read_pos() < old_journal->get_write_pos() &&
@@ -881,9 +864,7 @@ void MDLog::_reformat_journal(JournalPointer const &jp_in, Journaler *old_journa
       old_journal->wait_for_readable(&readable_waiter);
 
       // Wait for a journal prefetch to complete
-      mds->mds_lock.Unlock();
       readable_waiter.wait();
-      mds->mds_lock.Lock();
     }
     if (old_journal->get_error()) {
       r = old_journal->get_error();
@@ -906,18 +887,11 @@ void MDLog::_reformat_journal(JournalPointer const &jp_in, Journaler *old_journa
     // Write (buffered, synchronous) one serialized LogEvent
     events_transcribed += 1;
     new_journal->append_entry(bl);
-
-    // Allow other I/O to advance, e.g. MDS beacons
-    mds->mds_lock.Unlock();
-    mds->mds_lock.Lock();
   }
-  mds->mds_lock.Unlock();
 
   dout(1) << "Transcribed " << events_transcribed << " events, flushing new journal" << dendl;
   C_SaferCond flush_waiter;
-  mds->mds_lock.Lock();
   new_journal->flush(&flush_waiter);
-  mds->mds_lock.Unlock();
   flush_waiter.wait();
 
   // If failed to rewrite journal, leave the part written journal
@@ -934,9 +908,7 @@ void MDLog::_reformat_journal(JournalPointer const &jp_in, Journaler *old_journa
   /* Delete the old journal to free space */
   dout(1) << "New journal flushed, erasing old journal" << dendl;
   C_SaferCond erase_waiter;
-  mds->mds_lock.Lock();
   old_journal->erase(&erase_waiter);
-  mds->mds_lock.Unlock();
   int erase_result = erase_waiter.wait();
   assert(erase_result == 0);
   delete old_journal;
@@ -962,7 +934,6 @@ void MDLog::_reformat_journal(JournalPointer const &jp_in, Journaler *old_journa
 // i am a separate thread
 void MDLog::_replay_thread()
 {
-  mds->mds_lock.Lock();
   dout(10) << "_replay_thread start" << dendl;
 
   // loop
@@ -997,9 +968,7 @@ void MDLog::_replay_thread()
            * -- as long as we drop the main mds lock--. */
           C_SaferCond reread_fin;
           journaler->reread_head(&reread_fin);
-          mds->mds_lock.Unlock();
           int err = reread_fin.wait();
-          mds->mds_lock.Lock();
           if (err) {
             if (err == -ENOENT && mds->is_standby_replay()) {
               r = -EAGAIN;
@@ -1081,10 +1050,6 @@ void MDLog::_replay_thread()
     delete le;
 
     logger->set(l_mdl_rdpos, pos);
-
-    // drop lock for a second, so other events/messages (e.g. beacon timer!) can go off
-    mds->mds_lock.Unlock();
-    mds->mds_lock.Lock();
   }
 
   // done!
@@ -1097,10 +1062,11 @@ void MDLog::_replay_thread()
   }
 
   dout(10) << "_replay_thread kicking waiters" << dendl;
+  mds->mds_lock.Lock();
   finish_contexts(g_ceph_context, waitfor_replay, r);  
+  mds->mds_lock.Unlock();
 
   dout(10) << "_replay_thread finish" << dendl;
-  mds->mds_lock.Unlock();
 }
 
 void MDLog::standby_trim_segments()