Re: [man-pages RFC PATCH v4] statx, inode: document the new STATX_INO_VERSION field

Theodore Ts'o
2022-09-09T13:49:21Z

On Fri, Sep 09, 2022 at 08:47:17AM -0400, Jeff Layton wrote:
>
> i_version only changes now if someone has queried it since it was last
> changed. That makes a huge difference in performance. We can try to
> optimize it further, but it probably wouldn't move the needle much under
> real workloads.

Good point. And to be clear, from NFS's perspective, you only need to
have i_version bumped if there is a user-visible change to the
file. --- with an explicit exception here of the FIEMAP system call,
since in the case of a delayed allocation, FIEMAP might change from
reporting:

ext: logical_offset: physical_offset: length: expected: flags:
0: 0.. 0: 0.. 0: 0: last,unknown_loc,delalloc,eof

to this:

ext: logical_offset: physical_offset: length: expected: flags:
0: 0.. 0: 190087172.. 190087172: 1: last,eof

after a sync(2) or fsync(2) call, or after time passes.

> Great! That's what I was hoping for with ext4. Would you be willing to
> pick up these two patches for v6.1?
>
> https://lore.kernel.org/linux-ext4/20220908172448.208585-3-jlayton@kernel.org/T/#u
> https://lore.kernel.org/linux-ext4/20220908172448.208585-4-jlayton@kernel.org/T/#u

I think you mean:

https://lore.kernel.org/linux-ext4/20220908172448.208585-2-jlayton@kernel.org/T/#u
https://lore.kernel.org/linux-ext4/20220908172448.208585-3-jlayton@kernel.org/T/#u

Right?

BTW, sorry for not responding to these patches earlier; between
preparing for the various Linux conferences in Dublin next week, and
being in Zurich and meeting with colleagues at $WORK all of this week,
I'm a bit behind on my patch reviews.

Cheers,

- Ted