writeback: remove unused nonblocking and congestion checks (gfs2)

No one is calling wb_writeback and write_cache_pages with
wbc.nonblocking=1 any more. And lumpy pageout will want to do
nonblocking writeback without the congestion wait.
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

fs/gfs2/aops.c

@@ -269,7 +269,6 @@ static int gfs2_write_jdata_pagevec(struct address_space *mapping,
 	pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 	unsigned offset = i_size & (PAGE_CACHE_SIZE-1);
 	unsigned nrblocks = nr_pages * (PAGE_CACHE_SIZE/inode->i_sb->s_blocksize);
-	struct backing_dev_info *bdi = mapping->backing_dev_info;
 	int i;
 	int ret;
 
@@ -313,11 +312,6 @@ static int gfs2_write_jdata_pagevec(struct address_space *mapping,
 
 		if (ret || (--(wbc->nr_to_write) <= 0))
 			ret = 1;
-		if (wbc->nonblocking && bdi_write_congested(bdi)) {
-			wbc->encountered_congestion = 1;
-			ret = 1;
-		}
-
 	}
 	gfs2_trans_end(sdp);
 	return ret;
@@ -338,7 +332,6 @@ static int gfs2_write_jdata_pagevec(struct address_space *mapping,
 static int gfs2_write_cache_jdata(struct address_space *mapping,
 				  struct writeback_control *wbc)
 {
-	struct backing_dev_info *bdi = mapping->backing_dev_info;
 	int ret = 0;
 	int done = 0;
 	struct pagevec pvec;
@@ -348,11 +341,6 @@ static int gfs2_write_cache_jdata(struct address_space *mapping,
 	int scanned = 0;
 	int range_whole = 0;
 
-	if (wbc->nonblocking && bdi_write_congested(bdi)) {
-		wbc->encountered_congestion = 1;
-		return 0;
-	}
-
 	pagevec_init(&pvec, 0);
 	if (wbc->range_cyclic) {
 		index = mapping->writeback_index; /* Start from prev offset */