Btrfs: Fixes for 2.6.28-rc API changes

* open/close_bdev_excl -> open/close_bdev_exclusive
* blkdev_issue_discard takes a GFP mask now
* Fix blkdev_issue_discard usage now that it is enabled

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index bfd1512..df05f51 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -419,7 +419,7 @@
 		/* open coding of lru_cache_add, also not exported */
 		page_cache_get(page);
 		if (!pagevec_add(&pvec, page))
-			__pagevec_lru_add(&pvec);
+			__pagevec_lru_add_file(&pvec);
 
 		end = last_offset + PAGE_CACHE_SIZE - 1;
 		/*
@@ -475,7 +475,7 @@
 		last_offset += PAGE_CACHE_SIZE;
 	}
 	if (pagevec_count(&pvec))
-		__pagevec_lru_add(&pvec);
+		__pagevec_lru_add_file(&pvec);
 	return 0;
 }