xfs: don't nest icloglock inside ic_callback_lock

It's completely unnecessary because callbacks are added to iclogs
without holding the icloglock, hence no amount of ordering between
the icloglock and ic_callback_lock will order the removal of
callbacks from the iclog.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index e93cac6b537816dd198bc7759b4e3fc8a5fcfed0..bb439094227575acce7edc44840a95e727afaced 100644 (file)
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -2773,11 +2773,8 @@ static void
 xlog_state_do_iclog_callbacks(
        struct xlog             *log,
        struct xlog_in_core     *iclog)
-               __releases(&log->l_icloglock)
-               __acquires(&log->l_icloglock)
 {
        trace_xlog_iclog_callbacks_start(iclog, _RET_IP_);
-       spin_unlock(&log->l_icloglock);
        spin_lock(&iclog->ic_callback_lock);
        while (!list_empty(&iclog->ic_callbacks)) {
                LIST_HEAD(tmp);
@@ -2789,12 +2786,6 @@ xlog_state_do_iclog_callbacks(
                spin_lock(&iclog->ic_callback_lock);
        }
 
-       /*
-        * Pick up the icloglock while still holding the callback lock so we
-        * serialise against anyone trying to add more callbacks to this iclog
-        * now we've finished processing.
-        */
-       spin_lock(&log->l_icloglock);
        spin_unlock(&iclog->ic_callback_lock);
        trace_xlog_iclog_callbacks_done(iclog, _RET_IP_);
 }
@@ -2836,13 +2827,12 @@ xlog_state_do_callback(
                                iclog = iclog->ic_next;
                                continue;
                        }
+                       spin_unlock(&log->l_icloglock);
 
-                       /*
-                        * Running callbacks will drop the icloglock which means
-                        * we'll have to run at least one more complete loop.
-                        */
-                       cycled_icloglock = true;
                        xlog_state_do_iclog_callbacks(log, iclog);
+                       cycled_icloglock = true;
+
+                       spin_lock(&log->l_icloglock);
                        if (XLOG_FORCED_SHUTDOWN(log))
                                wake_up_all(&iclog->ic_force_wait);
                        else