Re: [PATCH v8 3/7] fsdax: Replace mmap entry in case of CoW

[Christoph Hellwig]

On Sun, Aug 29, 2021 at 08:25:13PM +0800, Shiyang Ruan wrote:
> We replace the existing entry to the newly allocated one in case of CoW.
> Also, we mark the entry as PAGECACHE_TAG_TOWRITE so writeback marks this
> entry as writeprotected.  This helps us snapshots so new write
> pagefaults after snapshots trigger a CoW.

Nit: s/We r/R/ above.

> + * MAP_SYNC on a dax mapping guarantees dirty metadata is
> + * flushed on write-faults (non-cow), but not read-faults.
> + */
> +static bool dax_fault_is_synchronous(const struct iomap_iter *iter,
> +		struct vm_area_struct *vma)
> +{
> +	return (iter->flags & IOMAP_WRITE) && (vma->vm_flags & VM_SYNC)
> +		&& (iter->iomap.flags & IOMAP_F_DIRTY);
> +}
> +
> +static bool dax_fault_is_cow(const struct iomap_iter *iter)
> +{
> +	return (iter->flags & IOMAP_WRITE)
> +		&& (iter->iomap.flags & IOMAP_F_SHARED);
> +}

The && goes last on the first line, not at the beginning of the second.