From: Amir Goldstein <amir73il@gmail.com>
To: "Georg Müller" <georgmueller@gmx.net>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
overlayfs <linux-unionfs@vger.kernel.org>
Subject: Re: overlayfs: supporting O_TMPFILE
Date: Fri, 29 Oct 2021 01:37:49 +0300 [thread overview]
Message-ID: <CAOQ4uxh_P0fiV9gQOs9CLvB+xJpJT4hWfAFyKBx0A-TyxAma8Q@mail.gmail.com> (raw)
In-Reply-To: <951c68ed-3f0e-8d9b-6c10-690df778ecc2@gmx.net>
On Thu, Oct 28, 2021 at 11:41 PM Georg Müller <georgmueller@gmx.net> wrote:
>
> Hi,
>
> I was trying to implement .tmpfile for overlayfs inode_operations to support O_TMPFILE.
>
> Docker with aufs supports it, but this is deprecated and removed from current docker. I now have a work-around in my code (create tmpfile+unlink), but
> I thought it might be a good idea to have tmpfile support in overlayfs.
>
> I was trying to do it on my own, but I have some headaches to what is necessary to achieve the goal.
>
> From my understanding, I have to find the dentry for the upper dir (or workdir) and call vfs_tmpdir() for this, but I am running from oops to oops.
>
> Is there some hint what I have to do to achieve the goal?
>
You'd want to use ovl_create_object() and probably pass a tmpfile argument
then pass it on struct ovl_cattr to ovl_create_or_link() after that
it becomes more complicated. You'd need ovl_create_tempfile() like
ovl_create_upper().
You can follow xfs_generic_create() for some clues.
You need parts of ovl_instantiate() but not all of it - it's a mess.
Good luck!
Amir.
next prev parent reply other threads:[~2021-10-28 22:38 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-28 20:41 overlayfs: supporting O_TMPFILE Georg Müller
2021-10-28 22:37 ` Amir Goldstein [this message]
2021-10-29 12:54 ` Miklos Szeredi
2021-10-29 13:47 ` Georg Müller
2021-10-29 15:16 ` Georg Müller
2022-04-19 14:01 ` Georg Müller
2022-04-20 8:21 ` Amir Goldstein
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