On Fri, Aug 04, 2017 at 03:26:10PM -0700, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > This is a note to let you know that I've just added the patch titled > > Btrfs: use down_read_nested to make lockdep silent > > to the 4.4-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > btrfs-use-down_read_nested-to-make-lockdep-silent.patch > and it can be found in the queue-4.4 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. Oops no, this did not apply, somehow I missed that. If someone wants this in 4.4, please provide a working backport. thanks, greg k-h > >From foo@baz Fri Aug 4 15:15:51 PDT 2017 > From: Liu Bo <bo.li.liu@xxxxxxxxxx> > Date: Wed, 30 Nov 2016 16:11:04 -0800 > Subject: Btrfs: use down_read_nested to make lockdep silent > > From: Liu Bo <bo.li.liu@xxxxxxxxxx> > > > [ Upstream commit e321f8a801d7b4c40da8005257b05b9c2b51b072 ] > > If @block_group is not @used_bg, it'll try to get @used_bg's lock without > droping @block_group 's lock and lockdep has throwed a scary deadlock warning > about it. > Fix it by using down_read_nested. > > Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx> > Reviewed-by: David Sterba <dsterba@xxxxxxxx> > Signed-off-by: David Sterba <dsterba@xxxxxxxx> > Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > --- > fs/btrfs/extent-tree.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index e46e7fbe1b34..14a37ff0b9e3 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -7401,7 +7401,8 @@ btrfs_lock_cluster(struct btrfs_block_group_cache *block_group, > > spin_unlock(&cluster->refill_lock); > > - down_read(&used_bg->data_rwsem); > + /* We should only have one-level nested. */ > + down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING); > > spin_lock(&cluster->refill_lock); > if (used_bg == cluster->block_group) > -- > 2.13.4 > > > > Patches currently in stable-queue which might be from bo.li.liu@xxxxxxxxxx are > > queue-4.4/btrfs-adjust-outstanding_extents-counter-properly-when-dio-write-is-split.patch > queue-4.4/btrfs-use-down_read_nested-to-make-lockdep-silent.patch