From: Josef Bacik <josef@toxicpanda.com>
Date: Tue, 21 Jul 2020 10:22:19 -0400
Subject: btrfs: call btrfs_try_granting_tickets when reserving space
Git-commit: 99ffb43e5d4a0710fb094f3efbdf47f85f3b87c9
Patch-mainline: v5.10-rc1
References: bsc#1135481

If we have compression on we could free up more space than we reserved,
and thus be able to make a space reservation.  Add the call for this
scenario.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/block-group.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index bc95f5f963fb..c9d7465501a4 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -2961,6 +2961,13 @@ int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,
 						      space_info, -ram_bytes);
 		if (delalloc)
 			cache->delalloc_bytes += num_bytes;
+
+		/*
+		 * Compression can use less space than we reserved, so wake
+		 * tickets if that happens
+		 */
+		if (num_bytes < ram_bytes)
+			btrfs_try_granting_tickets(cache->fs_info, space_info);
 	}
 	spin_unlock(&cache->lock);
 	spin_unlock(&space_info->lock);