Btrfs: hold trans_mutex when using btrfs_record_root_in_trans

btrfs_record_root_in_trans needs the trans_mutex held to make sure two
callers don't race to setup the root in a given transaction.  This adds
it to all the places that were missing it.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 919172de5c9a..4112d53d4f4d 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -688,7 +688,9 @@ static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
                 num_bytes -= btrfs_root_used(&dirty->root->root_item);
                 bytes_used = btrfs_root_used(&root->root_item);
                 if (num_bytes) {
+                        mutex_lock(&root->fs_info->trans_mutex);
                         btrfs_record_root_in_trans(root);
+                        mutex_unlock(&root->fs_info->trans_mutex);
                         btrfs_set_root_used(&root->root_item,
                                             bytes_used - num_bytes);
                 }