Re: [PATCH v5 04/13] btrfs: add support for inserting raid stripe extents

[Christoph Hellwig <hch@infradead.org>]

> --- a/fs/btrfs/bio.h
> +++ b/fs/btrfs/bio.h
> @@ -58,6 +58,8 @@ struct btrfs_bio {
>  	atomic_t pending_ios;
>  	struct work_struct end_io_work;
>  
> +	struct work_struct raid_stripe_work;

You should be able to reused end_io_work here, as it is only used
for reads currently.

>  
> +static bool delayed_ref_needs_rst_update(struct btrfs_fs_info *fs_info,
> +					 struct btrfs_delayed_ref_head *head)
> +{
> +	struct extent_map *em;
> +	struct map_lookup *map;
> +	bool ret = false;
> +
> +	if (!btrfs_stripe_tree_root(fs_info))
> +		return ret;
> +
> +	em = btrfs_get_chunk_map(fs_info, head->bytenr, head->num_bytes);
> +	if (!em)
> +		return ret;
> +
> +	map = em->map_lookup;
> +
> +	if (btrfs_need_stripe_tree_update(fs_info, map->type))

This just seems very expensive.  Is there no way to propafate
this information without doign a chunk map lookup every time?

> --- a/fs/btrfs/zoned.c
> +++ b/fs/btrfs/zoned.c
> @@ -1687,6 +1687,10 @@ void btrfs_rewrite_logical_zoned(struct btrfs_ordered_extent *ordered)
>  	u64 *logical = NULL;
>  	int nr, stripe_len;
>  
> +	/* Filesystems with a stripe tree have their own l2p mapping */
> +	if (btrfs_stripe_tree_root(fs_info))
> +		return;

I don't think we should even be able to readch this, as the call to
btrfs_rewrite_logical_zoned is guarded by having a valid
ordered->physical… and that is only set in btrfs_simple_end_io.
So this could just be an assert.