GFS2: Merge gfs2_attach_bufdata() into trans.c

The locking in gfs2_attach_bufdata() was type specific (data/meta)
which made the function rather confusing. This patch moves the core
of gfs2_attach_bufdata() into trans.c renaming it gfs2_alloc_bufdata()
and moving the locking into gfs2_trans_add_data()/gfs2_trans_add_meta()

As a result all of the locking related to adding data and metadata to
the journal is now in these two functions. This should help to clarify
what is going on, and give us some opportunities to simplify in
some cases.

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

1 files changed, 26 insertions, 11 deletions

diff --git a/fs/gfs2/trans.c b/fs/gfs2/trans.c
index 1fbd57eafa48b6..14dbf6d3cdc0b4 100644
--- a/fs/gfs2/trans.c
+++ b/fs/gfs2/trans.c
@@ -143,6 +143,21 @@ void gfs2_trans_end(struct gfs2_sbd *sdp)
 	sb_end_intwrite(sdp->sd_vfs);
 }
 
+static struct gfs2_bufdata *gfs2_alloc_bufdata(struct gfs2_glock *gl,
+					       struct buffer_head *bh,
+					       const struct gfs2_log_operations *lops)
+{
+	struct gfs2_bufdata *bd;
+
+	bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
+	bd->bd_bh = bh;
+	bd->bd_gl = gl;
+	bd->bd_ops = lops;
+	INIT_LIST_HEAD(&bd->bd_list);
+	bh->b_private = bd;
+	return bd;
+}
+
 /**
  * databuf_lo_add - Add a databuf to the transaction.
  *
@@ -190,16 +205,15 @@ void gfs2_trans_add_data(struct gfs2_glock *gl, struct buffer_head *bh)
 	lock_buffer(bh);
 	gfs2_log_lock(sdp);
 	bd = bh->b_private;
-	if (bd)
-		gfs2_assert(sdp, bd->bd_gl == gl);
-	else {
+	if (bd == NULL) {
 		gfs2_log_unlock(sdp);
 		unlock_buffer(bh);
-		gfs2_attach_bufdata(gl, bh, 0);
-		bd = bh->b_private;
+		if (bh->b_private == NULL)
+			bd = gfs2_alloc_bufdata(gl, bh, &gfs2_databuf_lops);
 		lock_buffer(bh);
 		gfs2_log_lock(sdp);
 	}
+	gfs2_assert(sdp, bd->bd_gl == gl);
 	databuf_lo_add(sdp, bd);
 	gfs2_log_unlock(sdp);
 	unlock_buffer(bh);
@@ -240,16 +254,17 @@ void gfs2_trans_add_meta(struct gfs2_glock *gl, struct buffer_head *bh)
 	lock_buffer(bh);
 	gfs2_log_lock(sdp);
 	bd = bh->b_private;
-	if (bd)
-		gfs2_assert(sdp, bd->bd_gl == gl);
-	else {
+	if (bd == NULL) {
 		gfs2_log_unlock(sdp);
 		unlock_buffer(bh);
-		gfs2_attach_bufdata(gl, bh, 1);
-		bd = bh->b_private;
+		lock_page(bh->b_page);
+		if (bh->b_private == NULL)
+			bd = gfs2_alloc_bufdata(gl, bh, &gfs2_buf_lops);
+		unlock_page(bh->b_page);
 		lock_buffer(bh);
 		gfs2_log_lock(sdp);
 	}
+	gfs2_assert(sdp, bd->bd_gl == gl);
 	meta_lo_add(sdp, bd);
 	gfs2_log_unlock(sdp);
 	unlock_buffer(bh);
@@ -263,7 +278,7 @@ void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 	BUG_ON(!list_empty(&bd->bd_list));
 	BUG_ON(!list_empty(&bd->bd_ail_st_list));
 	BUG_ON(!list_empty(&bd->bd_ail_gl_list));
-	lops_init_le(bd, &gfs2_revoke_lops);
+	bd->bd_ops = &gfs2_revoke_lops;
 	tr->tr_touched = 1;
 	tr->tr_num_revoke++;
 	sdp->sd_log_num_revoke++;