Btrfs: Add root tree pointer transaction ids

This patch adds transaction IDs to root tree pointers.
Transaction IDs in tree pointers are compared with the
generation numbers in block headers when reading root
blocks of trees. This can detect some types of IO errors.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 835daed5561f..e0201c3a7dc9 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -117,6 +117,7 @@ int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 
         btrfs_set_root_bytenr(&root_item, leaf->start);
+        btrfs_set_root_generation(&root_item, trans->transid);
         btrfs_set_root_level(&root_item, 0);
         btrfs_set_root_refs(&root_item, 0);
         btrfs_set_root_used(&root_item, 0);
@@ -2065,6 +2066,7 @@ static int update_log_root(struct btrfs_trans_handle *trans,
                 return 0;
 
         btrfs_set_root_bytenr(&log->root_item, log->node->start);
+        btrfs_set_root_generation(&log->root_item, trans->transid);
         btrfs_set_root_level(&log->root_item, btrfs_header_level(log->node));
         ret = btrfs_update_root(trans, log->fs_info->log_root_tree,
                                 &log->root_key, &log->root_item);