[PATCH 4/5] Btrfs: fix unprotected extent map operation when logging file extents

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

We forget to protect the modified_extents list, fix it.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
 fs/btrfs/tree-log.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index cbb544e..f7e9387 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3525,8 +3525,10 @@ next_slot:
 		struct extent_map_tree *tree = &BTRFS_I(inode)->extent_tree;
 		struct extent_map *em, *n;
 
+		write_lock(&tree->lock);
 		list_for_each_entry_safe(em, n, &tree->modified_extents, list)
 			list_del_init(&em->list);
+		write_unlock(&tree->lock);
 	}
 
 	if (inode_only == LOG_INODE_ALL && S_ISDIR(inode->i_mode)) {
-- 
1.7.6.5