1. 09 Jul, 2020 1 commit
    • Filipe Manana's avatar
      btrfs: fix a block group ref counter leak after failure to remove block group · a39010dc
      Filipe Manana authored
      [ Upstream commit 9fecd132 ]
      
      When removing a block group, if we fail to delete the block group's item
      from the extent tree, we jump to the 'out' label and end up decrementing
      the block group's reference count once only (by 1), resulting in a counter
      leak because the block group at that point was already removed from the
      block group cache rbtree - so we have to decrement the reference count
      twice, once for the rbtree and once for our lookup at the start of the
      function.
      
      There is a second bug where if removing the free space tree entries (the
      call to remove_block_group_free_space()) fails we end up jumping to the
      'out_put_group' label but end up decrementing the reference count only
      once, when we should have done it twice, since we have already removed
      the block group from the block group cache rbtree. This happens because
      the reference count decrement for the rbtree reference happens after
      attempting to remove the free space tree entries, which is far away from
      the place where we remove the block group from the rbtree.
      
      To make things less error prone, decrement the reference count for the
      rbtree immediately after removing the block group from it. This also
      eleminates the need for two different exit labels on error, renaming
      'out_put_label' to just 'out' and removing the old 'out'.
      
      Fixes: f6033c5e ("btrfs: fix block group leak when removing fails")
      CC: stable@vger.kernel.org # 4.4+
      Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
      Reviewed-by: default avatarAnand Jain <anand.jain@oracle.com>
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
      a39010dc
  2. 30 Jun, 2020 39 commits