Re: [PATCH v4 00/54] tree-in-dcache stuff

Al Viro
2026-01-31T01:16:39Z

On Fri, Jan 30, 2026 at 05:05:34PM -0800, Samuel Wu wrote:

> > How lovely... Could you slap
> > WARN_ON(ret == -EAGAIN);
> > right before that
> > if (ret < 0)
> > return ret;
>
> Surprisingly ret == 0 every time, so no difference in dmesg logs with
> this addition.

What the hell? Other than that mutex_lock(), the only change in there
is the order of store to file->private_data and call of ffs_data_opened();
that struct file pointer is not visible to anyone at that point...

Wait, it also brings ffs_data_reset() on that transition under ffs->mutex...
For a quick check: does
git fetch git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git for-wsamuel2
git switch --detach FETCH_HEAD
demonstrate the same breakage?