[GFS2] Fix leak of gfs2_bufdata

This fixes a memory leak of struct gfs2_bufdata and also some
problems in the ordered write handling code. It needs a bit
more testing, but I believe that the reference counting of
ordered write buffers should now be correct.

This is aimed at fixing Red Hat bugzilla: #201028 and #201082
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/lops.c

@@ -464,7 +464,7 @@ static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
 	struct gfs2_inode *ip = GFS2_I(mapping->host);
 
 	tr->tr_touched = 1;
-	if (!list_empty(&bd->bd_list_tr) &&
+	if (list_empty(&bd->bd_list_tr) &&
 	    (ip->i_di.di_flags & GFS2_DIF_JDATA)) {
 		tr->tr_num_buf++;
 		list_add(&bd->bd_list_tr, &tr->tr_list_buf);
@@ -473,7 +473,7 @@ static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
 	}
 	gfs2_trans_add_gl(bd->bd_gl);
 	gfs2_log_lock(sdp);
-	if (!list_empty(&le->le_list)) {
+	if (list_empty(&le->le_list)) {
 		if (ip->i_di.di_flags & GFS2_DIF_JDATA)
 			sdp->sd_log_num_jdata++;
 		sdp->sd_log_num_databuf++;
@@ -640,10 +640,10 @@ static void databuf_lo_before_commit(struct gfs2_sbd *sdp)
 				 bd_le.le_list);
 		list_del(&bd1->bd_le.le_list);
 		sdp->sd_log_num_databuf--;
-
 		bh = bd1->bd_bh;
 		if (bh) {
 			bh->b_private = NULL;
+			get_bh(bh);
 			gfs2_log_unlock(sdp);
 			wait_on_buffer(bh);
 			brelse(bh);

fs/gfs2/meta_io.c

@@ -464,7 +464,6 @@ void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
 		lops_init_le(&bd->bd_le, &gfs2_buf_lops);
 	} else {
 		lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
-		get_bh(bh);
 	}
 	bh->b_private = bd;
 

fs/gfs2/ops_address.c

@@ -581,10 +581,8 @@ static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 	if (bd) {
 		bd->bd_bh = NULL;
 		bh->b_private = NULL;
-		gfs2_log_unlock(sdp);
-		brelse(bh);
-	} else
-		gfs2_log_unlock(sdp);
+	}
+	gfs2_log_unlock(sdp);
 
 	lock_buffer(bh);
 	clear_buffer_dirty(bh);
@@ -598,7 +596,7 @@ static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 
 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
 {
-	struct gfs2_sbd *sdp = page->mapping->host->i_sb->s_fs_info;
+	struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 	struct buffer_head *head, *bh, *next;
 	unsigned int curr_off = 0;
 

fs/gfs2/ops_super.c

@@ -216,8 +216,6 @@ static int gfs2_statfs(struct dentry *dentry, struct kstatfs *buf)
 	if (error)
 		return error;
 
-	memset(buf, 0, sizeof(struct kstatfs));
-
 	buf->f_type = GFS2_MAGIC;
 	buf->f_bsize = sdp->sd_sb.sb_bsize;
 	buf->f_blocks = sc.sc_total;