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

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

[gregkh]

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>

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 384659dc7818..540a7a63601e 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -2661,7 +2661,7 @@ int btrfs_update_block_group(struct btrfs_trans_handle *trans,
 		 * is because we need the unpinning stage to actually add the
 		 * space back to the block group, otherwise we will leak space.
 		 */
-		if (!alloc && cache->cached == BTRFS_CACHE_NO)
+		if (!alloc && !btrfs_block_group_cache_done(cache))
 			btrfs_cache_block_group(cache, 1);
 
 		byte_in_group = bytenr - cache->key.objectid;

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]

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