[PATCH stable-5.4] backport enospc issues during balance

Patch 1 is a preparatory patch to reduce conflicts. Patch 2 fixes balance failure due to ENOSPC in btrfs/156 on arm64 systems with pagesize=64k. Minor conflicts in fs/btrfs/block-group.c are resolved. Thanks.

Josef Bacik (2): btrfs: don't pass system_chunk into can_overcommit btrfs: take overcommit into account in inc_block_group_ro

fs/btrfs/block-group.c | 38 ++++++++++++++++++++++---------- fs/btrfs/space-info.c | 50 +++++++++++++++++------------------------- fs/btrfs/space-info.h | 3 +++ 3 files changed, 49 insertions(+), 42 deletions(-)