Bug#23251517: SEMISYNC REPLICATION HANGING

Revert following bug fix:

Bug#20685029: SLAVE IO THREAD SHOULD STOP WHEN DISK IS
FULL
Bug#21753696: MAKE SHOW SLAVE STATUS NON BLOCKING IF IO
THREAD WAITS FOR DISK SPACE

This fix results in a deadlock between slave IO thread
and SQL thread.

5 files changed, 21 insertions, 101 deletions

diff --git a/sql/log.cc b/sql/log.cc
index e0ba93b0959..50d7762af6d 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -37,7 +37,6 @@
 #include "log_event.h"          // Query_log_event
 #include "rpl_filter.h"
 #include "rpl_rli.h"
-#include "rpl_mi.h"
 #include "sql_audit.h"
 
 #include "sql_show.h"
@@ -4378,23 +4377,14 @@ end:
 }
 
 
-#ifdef HAVE_REPLICATION
-bool MYSQL_BIN_LOG::append(Log_event* ev,  Master_info *mi)
+bool MYSQL_BIN_LOG::append(Log_event* ev)
 {
   bool error = 0;
-  mysql_mutex_assert_owner(&mi->data_lock);
   mysql_mutex_lock(&LOCK_log);
   DBUG_ENTER("MYSQL_BIN_LOG::append");
 
   DBUG_ASSERT(log_file.type == SEQ_READ_APPEND);
   /*
-    Release data_lock by holding LOCK_log, while writing into the relay log.
-    If slave IO thread waits here for free space, we don't want
-    SHOW SLAVE STATUS to hang on mi->data_lock. Note LOCK_log mutex is
-    sufficient to block SQL thread when IO thread is updating relay log here.
-  */
-  mysql_mutex_unlock(&mi->data_lock);
-  /*
     Log_event::write() is smart enough to use my_b_write() or
     my_b_append() depending on the kind of cache we have.
   */
@@ -4408,58 +4398,24 @@ bool MYSQL_BIN_LOG::append(Log_event* ev,  Master_info *mi)
   if (flush_and_sync(0))
     goto err;
   if ((uint) my_b_append_tell(&log_file) > max_size)
-  {
-    /*
-      If rotation is required we must acquire data_lock to protect
-      description_event from clients executing FLUSH LOGS in parallel.
-      In order do that we must release the existing LOCK_log so that we
-      get it once again in proper locking order to avoid dead locks.
-      i.e data_lock , LOCK_log.
-    */
-    mysql_mutex_unlock(&LOCK_log);
-    mysql_mutex_lock(&mi->data_lock);
-    mysql_mutex_lock(&LOCK_log);
     error= new_file_without_locking();
-    /*
-      After rotation release data_lock, we need the LOCK_log till we signal
-      the updation.
-    */
-    mysql_mutex_unlock(&mi->data_lock);
-  }
 err:
-  signal_update();				// Safe as we don't call close
   mysql_mutex_unlock(&LOCK_log);
-  mysql_mutex_lock(&mi->data_lock);
+  signal_update();				// Safe as we don't call close
   DBUG_RETURN(error);
 }
 
 
-bool MYSQL_BIN_LOG::appendv(Master_info* mi, const char* buf, uint len,...)
+bool MYSQL_BIN_LOG::appendv(const char* buf, uint len,...)
 {
   bool error= 0;
   DBUG_ENTER("MYSQL_BIN_LOG::appendv");
   va_list(args);
   va_start(args,len);
 
-  mysql_mutex_assert_owner(&mi->data_lock);
-  mysql_mutex_lock(&LOCK_log);
   DBUG_ASSERT(log_file.type == SEQ_READ_APPEND);
 
-  /*
-    Release data_lock by holding LOCK_log, while writing into the relay log.
-    If slave IO thread waits here for free space, we don't want
-    SHOW SLAVE STATUS to hang on mi->data_lock. Note LOCK_log mutex is
-    sufficient to block SQL thread when IO thread is updating relay log here.
-  */
-  mysql_mutex_unlock(&mi->data_lock);
-  DBUG_EXECUTE_IF("simulate_io_thd_wait_for_disk_space",
-                  {
-                  const char act[]= "disk_full_reached SIGNAL parked";
-                  DBUG_ASSERT(opt_debug_sync_timeout > 0);
-                  DBUG_ASSERT(!debug_sync_set_action(current_thd,
-                                                     STRING_WITH_LEN(act)));
-                  };);
-
+  mysql_mutex_assert_owner(&LOCK_log);
   do
   {
     if (my_b_append(&log_file,(uchar*) buf,len))
@@ -4472,34 +4428,13 @@ bool MYSQL_BIN_LOG::appendv(Master_info* mi, const char* buf, uint len,...)
   DBUG_PRINT("info",("max_size: %lu",max_size));
   if (flush_and_sync(0))
     goto err;
-  if ((uint) my_b_append_tell(&log_file) >
-      DBUG_EVALUATE_IF("rotate_slave_debug_group", 500, max_size))
-  {
-    /*
-      If rotation is required we must acquire data_lock to protect
-      description_event from clients executing FLUSH LOGS in parallel.
-      In order do that we must release the existing LOCK_log so that we
-      get it once again in proper locking order to avoid dead locks.
-      i.e data_lock , LOCK_log.
-    */
-    mysql_mutex_unlock(&LOCK_log);
-    mysql_mutex_lock(&mi->data_lock);
-    mysql_mutex_lock(&LOCK_log);
+  if ((uint) my_b_append_tell(&log_file) > max_size)
     error= new_file_without_locking();
-    /*
-      After rotation release data_lock, we need the LOCK_log till we signal
-      the updation.
-    */
-    mysql_mutex_unlock(&mi->data_lock);
-  }
 err:
   if (!error)
     signal_update();
-  mysql_mutex_unlock(&LOCK_log);
-  mysql_mutex_lock(&mi->data_lock);
   DBUG_RETURN(error);
 }
-#endif
 
 bool MYSQL_BIN_LOG::flush_and_sync(bool *synced)
 {
diff --git a/sql/log.h b/sql/log.h
index dd09cb41026..b5e751386a6 100644
--- a/sql/log.h
+++ b/sql/log.h
@@ -20,7 +20,6 @@
 #include "handler.h"                            /* my_xid */
 
 class Relay_log_info;
-class Master_info;
 
 class Format_description_log_event;
 
@@ -455,8 +454,8 @@ public:
     v stands for vector
     invoked as appendv(buf1,len1,buf2,len2,...,bufn,lenn,0)
   */
-  bool appendv(Master_info* mi, const char* buf,uint len,...);
-  bool append(Log_event* ev, Master_info* mi);
+  bool appendv(const char* buf,uint len,...);
+  bool append(Log_event* ev);
 
   void make_log_name(char* buf, const char* log_ident);
   bool is_active(const char* log_file_name);
diff --git a/sql/slave.cc b/sql/slave.cc
index 31037c453d3..acf68e231f3 100644
--- a/sql/slave.cc
+++ b/sql/slave.cc
@@ -1660,7 +1660,7 @@ Waiting for the slave SQL thread to free enough relay log space");
 #endif
     if (rli->sql_force_rotate_relay)
     {
-      rotate_relay_log(rli->mi, true/*need_data_lock=true*/);
+      rotate_relay_log(rli->mi);
       rli->sql_force_rotate_relay= false;
     }
 
@@ -1705,7 +1705,7 @@ static void write_ignored_events_info_to_relay_log(THD *thd, Master_info *mi)
     if (likely((bool)ev))
     {
       ev->server_id= 0; // don't be ignored by slave SQL thread
-      if (unlikely(rli->relay_log.append(ev, mi)))
+      if (unlikely(rli->relay_log.append(ev)))
         mi->report(ERROR_LEVEL, ER_SLAVE_RELAY_LOG_WRITE_FAILURE,
                    ER(ER_SLAVE_RELAY_LOG_WRITE_FAILURE),
                    "failed to write a Rotate event"
@@ -3605,7 +3605,7 @@ static int process_io_create_file(Master_info* mi, Create_file_log_event* cev)
           break;
         Execute_load_log_event xev(thd,0,0);
         xev.log_pos = cev->log_pos;
-        if (unlikely(mi->rli.relay_log.append(&xev, mi)))
+        if (unlikely(mi->rli.relay_log.append(&xev)))
         {
           mi->report(ERROR_LEVEL, ER_SLAVE_RELAY_LOG_WRITE_FAILURE,
                      ER(ER_SLAVE_RELAY_LOG_WRITE_FAILURE),
@@ -3619,7 +3619,7 @@ static int process_io_create_file(Master_info* mi, Create_file_log_event* cev)
       {
         cev->block = net->read_pos;
         cev->block_len = num_bytes;
-        if (unlikely(mi->rli.relay_log.append(cev, mi)))
+        if (unlikely(mi->rli.relay_log.append(cev)))
         {
           mi->report(ERROR_LEVEL, ER_SLAVE_RELAY_LOG_WRITE_FAILURE,
                      ER(ER_SLAVE_RELAY_LOG_WRITE_FAILURE),
@@ -3634,7 +3634,7 @@ static int process_io_create_file(Master_info* mi, Create_file_log_event* cev)
         aev.block = net->read_pos;
         aev.block_len = num_bytes;
         aev.log_pos = cev->log_pos;
-        if (unlikely(mi->rli.relay_log.append(&aev, mi)))
+        if (unlikely(mi->rli.relay_log.append(&aev)))
         {
           mi->report(ERROR_LEVEL, ER_SLAVE_RELAY_LOG_WRITE_FAILURE,
                      ER(ER_SLAVE_RELAY_LOG_WRITE_FAILURE),
@@ -3713,7 +3713,7 @@ static int process_io_rotate(Master_info *mi, Rotate_log_event *rev)
     Rotate the relay log makes binlog format detection easier (at next slave
     start or mysqlbinlog)
   */
-  DBUG_RETURN(rotate_relay_log(mi, false/*need_data_lock=false*/));
+  DBUG_RETURN(rotate_relay_log(mi) /* will take the right mutexes */);
 }
 
 /*
@@ -3819,7 +3819,7 @@ static int queue_binlog_ver_1_event(Master_info *mi, const char *buf,
       Log_event::Log_event(const char* buf...) in log_event.cc).
       */
       ev->log_pos+= event_len; /* make log_pos be the pos of the end of the event */
-    if (unlikely(rli->relay_log.append(ev, mi)))
+    if (unlikely(rli->relay_log.append(ev)))
     {
       delete ev;
       mysql_mutex_unlock(&mi->data_lock);
@@ -3875,7 +3875,7 @@ static int queue_binlog_ver_3_event(Master_info *mi, const char *buf,
     inc_pos= event_len;
     break;
   }
-  if (unlikely(rli->relay_log.append(ev, mi)))
+  if (unlikely(rli->relay_log.append(ev)))
   {
     delete ev;
     mysql_mutex_unlock(&mi->data_lock);
@@ -4083,6 +4083,7 @@ static int queue_event(Master_info* mi,const char* buf, ulong event_len)
      direct master (an unsupported, useless setup!).
   */
 
+  mysql_mutex_lock(log_lock);
   s_id= uint4korr(buf + SERVER_ID_OFFSET);
   if ((s_id == ::server_id && !mi->rli.replicate_same_server_id) ||
       /*
@@ -4115,7 +4116,6 @@ static int queue_event(Master_info* mi,const char* buf, ulong event_len)
       IGNORE_SERVER_IDS it increments mi->master_log_pos
       as well as rli->group_relay_log_pos.
     */
-    mysql_mutex_lock(log_lock);
     if (!(s_id == ::server_id && !mi->rli.replicate_same_server_id) ||
         (buf[EVENT_TYPE_OFFSET] != FORMAT_DESCRIPTION_EVENT &&
          buf[EVENT_TYPE_OFFSET] != ROTATE_EVENT &&
@@ -4127,14 +4127,13 @@ static int queue_event(Master_info* mi,const char* buf, ulong event_len)
       rli->ign_master_log_pos_end= mi->master_log_pos;
     }
     rli->relay_log.signal_update(); // the slave SQL thread needs to re-check
-    mysql_mutex_unlock(log_lock);
     DBUG_PRINT("info", ("master_log_pos: %lu, event originating from %u server, ignored",
                         (ulong) mi->master_log_pos, uint4korr(buf + SERVER_ID_OFFSET)));
   }
   else
   {
     /* write the event to the relay log */
-    if (likely(!(rli->relay_log.appendv(mi, buf,event_len,0))))
+    if (likely(!(rli->relay_log.appendv(buf,event_len,0))))
     {
       mi->master_log_pos+= inc_pos;
       DBUG_PRINT("info", ("master_log_pos: %lu", (ulong) mi->master_log_pos));
@@ -4144,10 +4143,9 @@ static int queue_event(Master_info* mi,const char* buf, ulong event_len)
     {
       error= ER_SLAVE_RELAY_LOG_WRITE_FAILURE;
     }
-    mysql_mutex_lock(log_lock);
     rli->ign_master_log_name_end[0]= 0; // last event is not ignored
-    mysql_mutex_unlock(log_lock);
   }
+  mysql_mutex_unlock(log_lock);
 
 skip_relay_logging:
   
@@ -5007,21 +5005,11 @@ err:
   locks; here we don't, so this function is mainly taking locks).
   Returns nothing as we cannot catch any error (MYSQL_BIN_LOG::new_file()
   is void).
-
-  @param mi Master_info for the IO thread.
-  @param need_data_lock If true, mi->data_lock will be acquired otherwise,
-  mi->data_lock must be held by the caller.
 */
 
-int rotate_relay_log(Master_info* mi, bool need_data_lock)
+int rotate_relay_log(Master_info* mi)
 {
   DBUG_ENTER("rotate_relay_log");
-  if (need_data_lock)
-    mysql_mutex_lock(&mi->data_lock);
-  else
-  {
-    mysql_mutex_assert_owner(&mi->data_lock);
-  }
   Relay_log_info* rli= &mi->rli;
   int error= 0;
 
@@ -5056,8 +5044,6 @@ int rotate_relay_log(Master_info* mi, bool need_data_lock)
   */
   rli->relay_log.harvest_bytes_written(&rli->log_space_total);
 end:
-  if (need_data_lock)
-    mysql_mutex_unlock(&mi->data_lock);
   DBUG_RETURN(error);
 }
 
diff --git a/sql/slave.h b/sql/slave.h
index 0cf8adb0315..7bf136694cc 100644
--- a/sql/slave.h
+++ b/sql/slave.h
@@ -205,7 +205,7 @@ int purge_relay_logs(Relay_log_info* rli, THD *thd, bool just_reset,
 		     const char** errmsg);
 void set_slave_thread_options(THD* thd);
 void set_slave_thread_default_charset(THD *thd, Relay_log_info const *rli);
-int rotate_relay_log(Master_info* mi, bool need_data_lock);
+int rotate_relay_log(Master_info* mi);
 int apply_event_and_update_pos(Log_event* ev, THD* thd, Relay_log_info* rli);
 
 pthread_handler_t handle_slave_io(void *arg);
diff --git a/sql/sql_reload.cc b/sql/sql_reload.cc
index f24f31b6399..b29cc9a9433 100644
--- a/sql/sql_reload.cc
+++ b/sql/sql_reload.cc
@@ -157,7 +157,7 @@ bool reload_acl_and_cache(THD *thd, unsigned long options,
   {
 #ifdef HAVE_REPLICATION
     mysql_mutex_lock(&LOCK_active_mi);
-    if (rotate_relay_log(active_mi, true/*need_data_lock=true*/))
+    if (rotate_relay_log(active_mi))
       *write_to_binlog= -1;
     mysql_mutex_unlock(&LOCK_active_mi);
 #endif