On Wed, May 10, 2017 at 12:21 PM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: [...] > > My plan is to send a pull request to Linus for the const ino stuff, > and then leave the rest to 4.13. > > This is the list I have in my head for what's missing: > > - lookup origin dir for snapshots > - const ino for non-samefs > - correct d_ino for copied up entries > - NFS export support > - hardlink unbreaking [...] > > The non-starred ones don't seem too hard and should aim for 4.13. > Just to clarify, did you mean that we should aim for NFS export and hardlinks for 4.13 for samefs? or non-samefs? Because I can see how non-samefs is possible, but complicates the reverse inode map, so I rather start with samefs. It turns out that constant d_ino wasn't that hard. It's quite an isolated patch based on your old overlay.ino POC, see: https://github.com/amir73il/linux/tree/ovl-constino Basically, it's working and I also have xfstests to verify it, which I will post those and the patch later. I think that the toll on readdir performance is not such a big problem, because stat'ing the dir entries is served from cache, so 'ls -lR' is not going to suffer, only 'find -ino' with cold cache will suffer. There is still room for optimization for iterating 'very pure upper' dirs (with no copy ups in them). Amir.
