On 10/30/19 7:48 PM, Goldwyn Rodrigues wrote:
On 12:13 30/10, Shiyang Ruan wrote:
> This patchset aims to take care of this issue to make reflink and dedupe
> work correctly (actually in read/write path, there still has some problems,
> such as the page->mapping and page->index issue, in mmap path) in XFS under
> fsdax mode.
Have you managed to solve the problem of multi-mapped pages? I don't
think we can include this until we solve that problem. This is the
problem I faced when I was doing the btrfs dax support.
That problem still exists, didn't be solved in this patchset. But I am
also looking into it. As you know, it's a bit difficult.
Since the iomap for cow is merged in for-next tree, I think it's time to
update this in order to get some comments.
Suppose there is an extent shared with multiple files. You map data for
both files. Which inode should page->mapping->host (precisely
page->mapping) point to? As Dave pointed out, this needs to be fixed at
the mm level, and will not only benefit dax with CoW but other
areas such as overlayfs and possibly containers.
Yes, I will try to figure out a solution.