Btrfs: determine level of old roots
In btrfs_find_all_roots' termination condition, we compare the level of the
old buffer we got from btrfs_search_old_slot to the level of the current
root node. We'd better compare it to the level of the rewinded root node.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index f318793..65608fb 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -283,9 +283,7 @@
goto out;
}
- rcu_read_lock();
- root_level = btrfs_header_level(root->node);
- rcu_read_unlock();
+ root_level = btrfs_old_root_level(root, time_seq);
if (root_level + 1 == level)
goto out;
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index d9308c38..ef68c33 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1297,6 +1297,23 @@
return eb;
}
+int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq)
+{
+ struct tree_mod_elem *tm;
+ int level;
+
+ tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq);
+ if (tm && tm->op == MOD_LOG_ROOT_REPLACE) {
+ level = tm->old_root.level;
+ } else {
+ rcu_read_lock();
+ level = btrfs_header_level(root->node);
+ rcu_read_unlock();
+ }
+
+ return level;
+}
+
static inline int should_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 1630be8..34c5a442 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3120,6 +3120,7 @@
{
return atomic_inc_return(&fs_info->tree_mod_seq);
}
+int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq);
/* root-item.c */
int btrfs_find_root_ref(struct btrfs_root *tree_root,