From: Josef Bacik <jbacik@fb.com>
Date: Fri, 28 Sep 2018 07:18:00 -0400
Subject: btrfs: reset max_extent_size on clear in a bitmap
Git-commit: 553cceb49681d60975d00892877d4c871bf220f9
Patch-mainline: v4.20-rc1
References: bsc##1165949

We need to clear the max_extent_size when we clear bits from a bitmap
since it could have been from the range that contains the
max_extent_size.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/free-space-cache.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index a1f379e8ad13..67441219d6c9 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1687,6 +1687,8 @@ static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
 	bitmap_clear(info->bitmap, start, count);
 
 	info->bytes -= bytes;
+	if (info->max_extent_size > ctl->unit)
+		info->max_extent_size = 0;
 }
 
 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,