Re: [PATCH 0/3] fanotify support for btrfs sub-volumes

Christoph Hellwig
2023-11-06T17:13:26Z

On Mon, Nov 06, 2023 at 02:47:16PM +0100, Christian Brauner wrote:
> Granted, an over-generalization but non in any way different from
> claiming that currently on one needs to know about btrfs subvolumes or
> that the proposed vfsmount solution will make it magically so that no
> one needs to care anymore.

I don't think any one has claimed "no one" needs to care any more. What
the vfsmounts buy us that is that software that doesn't know and
should't know about btrfs subvolumes isn't silently broken. Software
that actually wants to do something fancy with them always need special
casing.

> Tools will have to change either way is my point. And a lot of tools do
> already handle subvolumes specially exactly because of the non-unique
> inode situation. And if they don't they still can get confused by seing
> st_dev numbers they can't associate with a filesystem.

Again, tools that actually are related to subvolume features are
not even the problem.