On Wed, May 23, 2018 at 02:34:40PM +0200, David Sterba wrote: > On Wed, May 23, 2018 at 10:16:55AM +0800, Su Yue wrote: > > >>> [ 47.692084] kernel BUG at fs/btrfs/locking.c:286! > > >> > > >> I saw the crash too but did not investigate the root cause. So I'll > > >> remove the branch from for-next until it's fixed. Thanks for the report. > > > > > > I think the problem stems from Qu's patch, which sets search_commit_root > > > =1 but doesn't set skip_locking, as a result we don't lock the tree when > > > we obtain a reference to the root node, yet later when traversing the > > > tree due to skip_locking not being set we try to lock it, and this > > > causes btrfs_assert_tree_locked to triggers. Can you test whether the > > > following diff solves the issues: > > > > > > > > > diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c > > > index bc19a7d11c98..23fadb640c59 100644 > > > --- a/fs/btrfs/qgroup.c > > > +++ b/fs/btrfs/qgroup.c > > > @@ -2702,6 +2702,7 @@ static void btrfs_qgroup_rescan_worker(struct > > > btrfs_work *work) > > > * should be recorded by qgroup > > > */ > > > path->search_commit_root = 1; > > > + path->skip_locking = 1; > > > > > > err = 0; > > > while (!err && !btrfs_fs_closing(fs_info)) { > > > > > > > > > If it does, this only means we need to make skip_locking = 1 being > > > conditional on search_commit_root being set and this situation should be > > > handled in btrfs_search_slot. > > > > After patching the change, btrfs/139 passes without BUG_ON. > > Confirmed, I've added the fixup to for-next, Liu Bo's branch is there to > and the crash did not show up.
Thanks a lot for the testing and fixes! thanks, -liubo -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html