[GFS2] Reorder writeback for glock sync

Previously we were doing (write data, wait for data, write metadata, wait
for metadata). After this patch we so (write metadata, write data, wait for
data, wait for metadata) which should be more efficient.

Also I noticed that the drop_bh and xmote_bh functions were almost
identical. In fact the only difference was a single test, and that
test is such that in the drop_bh case, it would always evaluate to
the correct result. As such we can use the xmote_bh functions in
all the places where we were using the drop_bh function and remove
the drop_bh functions.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 6 insertions, 7 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 159a5479c4e4..e668808b127f 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -947,8 +947,8 @@ static void gfs2_glock_drop_th(struct gfs2_glock *gl)
 	const struct gfs2_glock_operations *glops = gl->gl_ops;
 	unsigned int ret;
 
-	if (glops->go_drop_th)
-		glops->go_drop_th(gl);
+	if (glops->go_xmote_th)
+		glops->go_xmote_th(gl);
 
 	gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
 	gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
@@ -1252,12 +1252,11 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
 	list_del_init(&gh->gh_list);
 
 	if (list_empty(&gl->gl_holders)) {
-		spin_unlock(&gl->gl_spin);
-
-		if (glops->go_unlock)
+		if (glops->go_unlock) {
+			spin_unlock(&gl->gl_spin);
 			glops->go_unlock(gh);
-
-		spin_lock(&gl->gl_spin);
+			spin_lock(&gl->gl_spin);
+		}
 		gl->gl_stamp = jiffies;
 	}