On Thu, Oct 10, 2019 at 06:06:46PM +0300, Nikolay Borisov wrote:
> Since the filesystem is not well formed and no trees are loaded it's
> pointless holding the objectid_mutex. Just remove its usage.
Yes.
There's a case when the lock should be kept even in that phase, so we
could add a lockdep assertion, but I found btrfs_recover_log_trees with
a comment why the lock is not needed. Given that
btrfs_find_highest_objectid is used only in a hadnful places, I think
we're fine with just the comments.
> Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>
> ---
> fs/btrfs/disk-io.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index b850988023aa..72580eb6b706 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -2603,17 +2603,14 @@ int __cold init_tree_roots(struct btrfs_fs_info *fs_info)
> tree_root->commit_root = btrfs_root_node(tree_root);
> btrfs_set_root_refs(&tree_root->root_item, 1);
>
> - mutex_lock(&tree_root->objectid_mutex);
/*
* We don't need to hold objectid_mutex because ...
*/
> ret = btrfs_find_highest_objectid(tree_root,
> &tree_root->highest_objectid);
> if (ret) {
> - mutex_unlock(&tree_root->objectid_mutex);
> handle_error = true;
> continue;
> }
