Re: FAILED: patch "[PATCH] btrfs: use btrfs_block_group_cache_done in update_block_group" failed to apply to 5.3-stable tree

[Sasha Levin <sashal@kernel.org>]

On Sun, Dec 15, 2019 at 12:08:38PM +0100, gregkh@linuxfoundation.org wrote:
>
>The patch below does not apply to the 5.3-stable tree.
>If someone wants it applied there, or to any other stable or longterm
>tree, then please email the backport, including the original git commit
>id to <stable@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From a60adce85f4bb5c1ef8ffcebadd702cafa2f3696 Mon Sep 17 00:00:00 2001
>From: Josef Bacik <josef@toxicpanda.com>
>Date: Tue, 24 Sep 2019 16:50:44 -0400
>Subject: [PATCH] btrfs: use btrfs_block_group_cache_done in update_block_group
>
>When free'ing extents in a block group we check to see if the block
>group is not cached, and then cache it if we need to.  However we'll
>just carry on as long as we're loading the cache.  This is problematic
>because we are dirtying the block group here.  If we are fast enough we
>could do a transaction commit and clear the free space cache while we're
>still loading the space cache in another thread.  This truncates the
>free space inode, which will keep it from loading the space cache.
>
>Fix this by using the btrfs_block_group_cache_done helper so that we try
>to load the space cache unconditionally here, which will result in the
>caller waiting for the fast caching to complete and keep us from
>truncating the free space inode.
>
>CC: stable@vger.kernel.org # 4.4+
>Signed-off-by: Josef Bacik <josef@toxicpanda.com>
>Reviewed-by: Nikolay Borisov <nborisov@suse.com>
>Signed-off-by: David Sterba <dsterba@suse.com>

The code just moved around a lot. I've fixed it up and queued for all
branches.

-- 
Thanks,
Sasha