Re: [PATCH 20/42] btrfs: don't use ctl->free_space for max_extent_size

[Filipe Manana <fdmanana@gmail.com>]

On Thu, Oct 11, 2018 at 8:57 PM Josef Bacik <josef@toxicpanda.com> wrote:
>
> From: Josef Bacik <jbacik@fb.com>
>
> max_extent_size is supposed to be the largest contiguous range for the
> space info, and ctl->free_space is the total free space in the block
> group.  We need to keep track of these separately and _only_ use the
> max_free_space if we don't have a max_extent_size, as that means our
> original request was too large to search any of the block groups for and
> therefore wouldn't have a max_extent_size set.
>
> Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>

> ---
>  fs/btrfs/extent-tree.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 6e7bc3197737..4f48d047a1ec 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -7496,6 +7496,7 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
>         struct btrfs_block_group_cache *block_group = NULL;
>         u64 search_start = 0;
>         u64 max_extent_size = 0;
> +       u64 max_free_space = 0;
>         u64 empty_cluster = 0;
>         struct btrfs_space_info *space_info;
>         int loop = 0;
> @@ -7791,8 +7792,8 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
>                         spin_lock(&ctl->tree_lock);
>                         if (ctl->free_space <
>                             num_bytes + empty_cluster + empty_size) {
> -                               if (ctl->free_space > max_extent_size)
> -                                       max_extent_size = ctl->free_space;
> +                               max_free_space = max(max_free_space,
> +                                                    ctl->free_space);
>                                 spin_unlock(&ctl->tree_lock);
>                                 goto loop;
>                         }
> @@ -7959,6 +7960,8 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
>         }
>  out:
>         if (ret == -ENOSPC) {
> +               if (!max_extent_size)
> +                       max_extent_size = max_free_space;
>                 spin_lock(&space_info->lock);
>                 space_info->max_extent_size = max_extent_size;
>                 spin_unlock(&space_info->lock);
> --
> 2.14.3
>


-- 
Filipe David Manana,

“Whether you think you can, or you think you can't — you're right.”