fs: rename buffer trylock

Like the page lock change, this also requires name change, so convert the
raw test_and_set bitop to a trylock.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index fa73179..fa47e43 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -1104,7 +1104,7 @@
 			 * that we are writing into for the first time.
 			 */
 			type = IOMAP_NEW;
-			if (!test_and_set_bit(BH_Lock, &bh->b_state)) {
+			if (trylock_buffer(bh)) {
 				ASSERT(buffer_mapped(bh));
 				if (iomap_valid)
 					all_bh = 1;