The patch below does not apply to the 4.9-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 21a94f7acf0f748599ea552af5d9ee7d7e41c72f Mon Sep 17 00:00:00 2001
From: Josef Bacik josef@toxicpanda.com Date: Thu, 11 Oct 2018 15:54:03 -0400 Subject: [PATCH] btrfs: reset max_extent_size properly
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@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana fdmanana@suse.com Signed-off-by: Josef Bacik josef@toxicpanda.com Signed-off-by: David Sterba dsterba@suse.com
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index b6d930356dd3..87d6666cd8e3 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4565,6 +4565,7 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags, goto out; } else { ret = 1; + space_info->max_extent_size = 0; }
space_info->force_alloc = CHUNK_ALLOC_NO_FORCE; @@ -6459,6 +6460,7 @@ static void btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache, 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;