From: Liu Bo <liubo2009 <at> cn.fujitsu.com>
Subject: [PATCH] Btrfs: use do_div to avoid compile errors on 32bit box
Date: 2011-08-19 09:48:44 GMT (3 hours and 36 minutes ago)

When doing div operation of u64 type, we need to be careful and use do_div
to avoid compile ERROR on 32bit box:

"ERROR: "__udivdi3" [fs/btrfs/btrfs.ko] undefined!
make[1]: *** [__modpost] Error 1

Signed-off-by: Liu Bo <liubo2009 <at> cn.fujitsu.com>
---
 fs/btrfs/extent-tree.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 80d6148..9b495ce 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6796,14 +6796,14 @@ int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
 	index = get_block_group_index(block_group);
 	if (index == 0) {
 		dev_min = 4;
-		min_free /= 2;
+		do_div(min_free, 2);
 	} else if (index == 1) {
 		dev_min = 2;
 	} else if (index == 2) {
 		min_free *= 2;
 	} else if (index == 3) {
 		dev_min = fs_devices->rw_devices;
-		min_free /= dev_min;
+		do_div(min_free, dev_min);
 	}

 	mutex_lock(&root->fs_info->chunk_mutex);
-- 
1.6.5.2