Please add d55966c4279bfc6 to 5.4.x and 5.5.x

Hi,

I'd like to ask the stable team to add the patch

d55966c4279bfc6a0cf0b32bf13f5df228a1eeb6 btrfs: do not zero f_bavail if we have available space

to 5.4 and 5.5 stable trees as early as possible.

I'm not familiar with your release schedules but I saw the large patch sets for review and I hope I could squeeze that one in the upcoming release.

The commit fixes a problem in 'df' that causes false alerts and there are a lot of users hitting it. The patch itself is a one-liner, but with a high impact on usability.

Thanks in advance.