Re: [PATCH v2] btrfs: reject refs=0 subvolume without DEAD in SUBVOL_SYNC_WAIT

[Qu Wenruo]

在 2026/11/10 05:17, David Sterba 写道:
> On Sun, Nov 01, 2026 at 05:48:21PM +1030, Qu Wenruo wrote:
> > With that said, there are more problems with the ioctl.
> >
> > - No real user
> >     No one is utilizing BTRFS_SUBVOL_SYNC* flags. Btrfs-progs itself
> >     doesn't even bother it.
> >
> >     So all these fixes are very low priority, unless there are some wild
> >     programs utilizing this.
> >
> >     But even btrfs-progs doesn't utilize them, the possibility are very
> >     low.
>
> Obviously the ioctl was added so progs 'subvol sync' can use it for
> non-root users. I started working on it but there's a problem with the
> behaviour change between the user types. Root has full access and
> reports the progress while with this ioctl there were some problems I
> don't remember. The ioctl was designed to emulate all modes that root
> can do so it should be possible to get 1:1 output.

Are you still planning to implement the full root-less subvolume wait in 
progs?

Or is this feature deprecated and we can eventually remove it to reduce 
LLM bug reports?