[GFS2] Split gfs2_writepage into three cases

This patch splits gfs2_writepage into separate functions for each of
the three cases: writeback, ordered and journalled. As a result
it becomes a lot easier to see what each one is doing. The common
code is moved into gfs2_writepage_common.

This fixes a performance bug where we were doing more work than
strictly required in the ordered write case.

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

1 files changed, 10 insertions, 7 deletions

diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index 6c27cea761c6..e901f8f7d650 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -556,17 +556,20 @@ static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
 
         lock_buffer(bd->bd_bh);
         gfs2_log_lock(sdp);
-        if (!list_empty(&bd->bd_list_tr))
-                goto out;
-        tr->tr_touched = 1;
-        if (gfs2_is_jdata(ip)) {
-                tr->tr_num_buf++;
-                list_add(&bd->bd_list_tr, &tr->tr_list_buf);
+        if (tr) {
+                if (!list_empty(&bd->bd_list_tr))
+                        goto out;
+                tr->tr_touched = 1;
+                if (gfs2_is_jdata(ip)) {
+                        tr->tr_num_buf++;
+                        list_add(&bd->bd_list_tr, &tr->tr_list_buf);
+                }
         }
         if (!list_empty(&le->le_list))
                 goto out;
 
-        __glock_lo_add(sdp, &bd->bd_gl->gl_le);
+        if (tr)
+                __glock_lo_add(sdp, &bd->bd_gl->gl_le);
         if (gfs2_is_jdata(ip)) {
                 gfs2_pin(sdp, bd->bd_bh);
                 tr->tr_num_databuf_new++;