btrfs: Use WARN_ON()'s return value in place of WARN_ON(1)

Use WARN_ON()'s return value in place of WARN_ON(1) for cleaner source
code that outputs a more descriptive warnings. Also fix the styling
warning of redundant braces that came up as a result of this fix.

Signed-off-by: Dulshani Gunawardhana <dulshani.gunawardhana89@gmail.com>
Reviewed-by: Zach Brown <zab@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 656b076..e0aab44 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -2464,10 +2464,8 @@
 		}
 	}
 
-	if (-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)) {
-		WARN_ON(1);
+	if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
 		btrfsic_dump_tree(state);
-	}
 
 	return 0;
 }
@@ -2907,7 +2905,7 @@
 		btrfsic_release_block_ctx(&block_ctx);
 	}
 
-	if (!match) {
+	if (WARN_ON(!match)) {
 		printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
 		       " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
 		       " phys_bytenr=%llu)!\n",
@@ -2924,7 +2922,6 @@
 			       bytenr, block_ctx.dev->name,
 			       block_ctx.dev_bytenr, mirror_num);
 		}
-		WARN_ON(1);
 	}
 }