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/inode.c b/fs/btrfs/inode.c
index 1780022..ddecc9c 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2039,10 +2039,8 @@
 		key.offset = offset;
 
 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-	if (ret < 0) {
-		WARN_ON(1);
+	if (WARN_ON(ret < 0))
 		return ret;
-	}
 	ret = 0;
 
 	while (1) {
@@ -3182,8 +3180,7 @@
 
 		/* if we have links, this was a truncate, lets do that */
 		if (inode->i_nlink) {
-			if (!S_ISREG(inode->i_mode)) {
-				WARN_ON(1);
+			if (WARN_ON(!S_ISREG(inode->i_mode))) {
 				iput(inode);
 				continue;
 			}
@@ -8023,8 +8020,7 @@
 		if (ret == -EEXIST) {
 			/* we shouldn't get
 			 * eexist without a new_inode */
-			if (!new_inode) {
-				WARN_ON(1);
+			if (WARN_ON(!new_inode)) {
 				return ret;
 			}
 		} else {