Re: [PATCH 04/14] btrfs: use btrfs_read_node_slot in walk_down_reloc_tree

[Filipe Manana <fdmanana@gmail.com>]

On Thu, Nov 5, 2020 at 3:47 PM Josef Bacik <josef@toxicpanda.com> wrote:
>
> We do not need to call read_tree_block() here, simply use the
> btrfs_read_node_slot helper.
>
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>

Reviewed-by: Filipe Manana <fdmanana@suse.com>

I couldn't get anymore the lockdep splat I reported before (after
applying the whole patchset of course), it used to happen very often
with btrfs/033.

Looks good, thanks.

> ---
>  fs/btrfs/relocation.c | 15 ++-------------
>  1 file changed, 2 insertions(+), 13 deletions(-)
>
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index 0e2dd7cf87f6..d327b5b4f1cd 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -1415,10 +1415,8 @@ static noinline_for_stack
>  int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
>                          int *level)
>  {
> -       struct btrfs_fs_info *fs_info = root->fs_info;
>         struct extent_buffer *eb = NULL;
>         int i;
> -       u64 bytenr;
>         u64 ptr_gen = 0;
>         u64 last_snapshot;
>         u32 nritems;
> @@ -1426,8 +1424,6 @@ int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
>         last_snapshot = btrfs_root_last_snapshot(&root->root_item);
>
>         for (i = *level; i > 0; i--) {
> -               struct btrfs_key first_key;
> -
>                 eb = path->nodes[i];
>                 nritems = btrfs_header_nritems(eb);
>                 while (path->slots[i] < nritems) {
> @@ -1447,16 +1443,9 @@ int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
>                         return 0;
>                 }
>
> -               bytenr = btrfs_node_blockptr(eb, path->slots[i]);
> -               btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
> -               eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
> -                                    &first_key);
> -               if (IS_ERR(eb)) {
> +               eb = btrfs_read_node_slot(eb, path->slots[i]);
> +               if (IS_ERR(eb))
>                         return PTR_ERR(eb);
> -               } else if (!extent_buffer_uptodate(eb)) {
> -                       free_extent_buffer(eb);
> -                       return -EIO;
> -               }
>                 BUG_ON(btrfs_header_level(eb) != i - 1);
>                 path->nodes[i - 1] = eb;
>                 path->slots[i - 1] = 0;
> --
> 2.26.2
>


-- 
Filipe David Manana,

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