[PATCH v7] iomap: make inline data support more flexible

[Christoph Hellwig]

> Subject: iomap: Support tail packing

I can't say I like this "tail packing" language here when we have the
perfectly fine inline wording.  Same for various comments in the actual
code.

> +	/* inline and tail-packed data must start page aligned in the file */
> +	if (WARN_ON_ONCE(offset_in_page(iomap->offset)))
> +		return -EIO;
> +	if (WARN_ON_ONCE(size > PAGE_SIZE - offset_in_page(iomap->inline_data)))
> +		return -EIO;

Why can't we use iomap_inline_data_size_valid here? That is how can
size be different from iomap->legth?

Shouldn't the offset_in_page also go into iomap_inline_data_size_valid,
which should probably be called iomap_inline_data_valid then?

>  	if (iomap->type == IOMAP_INLINE) {
> +		int ret = iomap_read_inline_data(inode, page, iomap);
> +		return ret ?: PAGE_SIZE;

The ?: expression without the first leg is really confuing.  Especially
if a good old if is much more readable here.

		int ret = iomap_read_inline_data(inode, page, iomap);

		if (ret)
			return ret;
		return PAGE_SIZE;

> +		copied = copy_from_iter(iomap_inline_data(iomap, pos), length, iter);


> +		copied = copy_to_iter(iomap_inline_data(iomap, pos), length, iter);

Pleae avoid the overly long lines.