Btrfs: fix a tree mod logging issue for root replacement operations

Avoid the implicit free by tree_mod_log_set_root_pointer, which is wrong in
two places. Where needed, we call tree_mod_log_free_eb explicitly now.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 44a7e25..e6b75cc 100644 (file)
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -647,8 +647,6 @@ tree_mod_log_insert_root(struct btrfs_fs_info *fs_info,
        if (tree_mod_dont_log(fs_info, NULL))
                return 0;
 
-       __tree_mod_log_free_eb(fs_info, old_root);
-
        ret = tree_mod_alloc(fs_info, flags, &tm);
        if (ret < 0)
                goto out;
@@ -926,12 +924,7 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
                        ret = btrfs_dec_ref(trans, root, buf, 1, 1);
                        BUG_ON(ret); /* -ENOMEM */
                }
-               /*
-                * don't log freeing in case we're freeing the root node, this
-                * is done by tree_mod_log_set_root_pointer later
-                */
-               if (buf != root->node && btrfs_header_level(buf) != 0)
-                       tree_mod_log_free_eb(root->fs_info, buf);
+               tree_mod_log_free_eb(root->fs_info, buf);
                clean_tree_block(trans, root, buf);
                *last_ref = 1;
        }
@@ -1728,6 +1721,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
                        goto enospc;
                }
 
+               tree_mod_log_free_eb(root->fs_info, root->node);
                tree_mod_log_set_root_pointer(root, child);
                rcu_assign_pointer(root->node, child);