linux-kernel - [PATCH 4.18 339/350] btrfs: reset max_extent

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Date:   Sun, 11 Nov 2018 14:23:23 -0800
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Filipe Manana <fdmanana@...e.com>,
        Josef Bacik <josef@...icpanda.com>,
        David Sterba <dsterba@...e.com>
Subject: [PATCH 4.18 339/350] btrfs: reset max_extent_size properly

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Josef Bacik <josef@...icpanda.com>

commit 21a94f7acf0f748599ea552af5d9ee7d7e41c72f upstream.

If we use up our block group before allocating a new one we'll easily
get a max_extent_size that's set really really low, which will result in
a lot of fragmentation.  We need to make sure we're resetting the
max_extent_size when we add a new chunk or add new space.

CC: stable@...r.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@...e.com>
Signed-off-by: Josef Bacik <josef@...icpanda.com>
Signed-off-by: David Sterba <dsterba@...e.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/btrfs/extent-tree.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4661,6 +4661,7 @@ again:
 			goto out;
 	} else {
 		ret = 1;
+		space_info->max_extent_size = 0;
 	}
 
 	space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
@@ -6576,6 +6577,7 @@ static int btrfs_free_reserved_bytes(str
 		space_info->bytes_readonly += num_bytes;
 	cache->reserved -= num_bytes;
 	space_info->bytes_reserved -= num_bytes;
+	space_info->max_extent_size = 0;
 
 	if (delalloc)
 		cache->delalloc_bytes -= num_bytes;