[PATCH] Btrfs: fix wrong csum clone when doing relocation

[Miao Xie <miaox@cn.fujitsu.com>]

From: Josef Bacik <jbacik@fusionio.com>

Patch "Btrfs: remove btrfs_sector_sum structure" introduced a problem
that we copied the checksum value to the wrong address when doing
relocation.

The reason is:
It is very likely that one ordered extent has two or more checksum
structures to keep the relative checksum value, and ->bytenr in each
checksum structure should point to the start of its extent, not the
start of the ordered extent. Fix it.

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
 fs/btrfs/relocation.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 35c0cf7..e3108e5 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4410,11 +4410,13 @@ int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
 	if (ret)
 		goto out;
 
+	disk_bytenr = ordered->start;
 	while (!list_empty(&list)) {
 		sums = list_entry(list.next, struct btrfs_ordered_sum, list);
 		list_del_init(&sums->list);
 
-		sums->bytenr = ordered->start;
+		sums->bytenr = disk_bytenr;
+		disk_bytenr += sums->len;
 
 		btrfs_add_ordered_sum(inode, ordered, sums);
 	}
-- 
1.8.1.4