protocol/server: Remove connection from conf->conns w.o. race

1) Adding the connection to conf->conns used to
happen in conf->mutex, but removing happened under conn->lock.
Fixed that as below.
When the connection object is created conn's ref, bind_ref count
is set to '1'. For bind_ref ref/unref happens under conf->mutex
whenever server_connection_get, put is called.
When bind_ref goes to '0' connection object is removed from
conf->conns under conf->mutex.  After it is removed from the list,
conn_unref is called outside the conf->mutex.
conn_ref/unref still happens under conn->lock.

2) Fixed races in server_connection_cleaup in grace_timer_handler
and server_setvolume.

Change-Id: Ie7b63b10f658af909a11c3327066667f5b7bd114
BUG: 801675
Signed-off-by: Pranith Kumar K <pranithk@gluster.com>
Reviewed-on: http://review.gluster.com/2911
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Reviewed-by: Vijay Bellur <vijay@gluster.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/xlators/protocol/server/src/server.h b/xlators/protocol/server/src/server.h
index c54454e3efe..6024d100b30 100644
--- a/xlators/protocol/server/src/server.h
+++ b/xlators/protocol/server/src/server.h
@@ -60,6 +60,7 @@ struct _server_connection {
         struct list_head    list;
         char               *id;
         int                 ref;
+        int                 bind_ref;
         pthread_mutex_t     lock;
         fdtable_t          *fdtable;
         struct _lock_table *ltable;
@@ -75,6 +76,10 @@ typedef struct _server_connection server_connection_t;
 server_connection_t *
 server_connection_get (xlator_t *this, const char *id);
 
+server_connection_t *
+server_connection_put (xlator_t *this, server_connection_t *conn,
+                       gf_boolean_t *detached);
+
 server_connection_t*
 server_conn_unref (server_connection_t *conn);