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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAOQ4uxh_P0fiV9gQOs9CLvB+xJpJT4hWfAFyKBx0A-TyxAma8Q@mail.gmail.com \
--to=amir73il@gmail.com \
--cc=georgmueller@gmx.net \
--cc=linux-unionfs@vger.kernel.org \
--cc=miklos@szeredi.hu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).