archive mirror
 help / color / mirror / Atom feed
From: Linus Torvalds <>
To: Miklos Szeredi <>, Al Viro <>
Cc: Linux Kernel Mailing List <>,
	linux-fsdevel <>,
Subject: Re: [GIT PULL] overlayfs update for 5.15
Date: Thu, 2 Sep 2021 09:35:24 -0700	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Thu, Sep 2, 2021 at 6:51 AM Miklos Szeredi <> wrote:
> The reason this touches so many files is that the ->get_acl() method now
> gets a "bool rcu" argument.  The ->get_acl() API was updated based on
> comments from Al and Linus:

That link might have been good in the individual commit message too,
but I did it in the merge commit instead.

I did notice that we now have a stale comment about ->get_acl() in fs/namei.c:

                acl = get_cached_acl_rcu(inode, ACL_TYPE_ACCESS);
                if (!acl)
                        return -EAGAIN;
                /* no ->get_acl() calls in RCU mode... */
                if (is_uncached_acl(acl))
                        return -ECHILD;

but we actually did the RCU-mode ->get_acl() call already in

Of course, get_cached_acl_rcu() only does it for ACL_DONT_CACHE, not
for ACL_NOT_CACHED, so RCU mode is still a bit special.

At some point we probably should make get_cached_acl_rcu() do the
right thing for a successful lookup with ACL_NOT_CACHED set too, and
actually install the newly looked-up ACL. But I haven't thought much
about locking (but I think it would be ok, we use "cmpxchg" to update
the cached entry).

This is just a "maybe fixme for the future" note about that comment
and about get_cached_acl_rcu() behavior. I've pulled this, and I think
we're ok, it's just a small oddity.


  reply	other threads:[~2021-09-02 16:35 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-02 13:51 [GIT PULL] overlayfs update for 5.15 Miklos Szeredi
2021-09-02 16:35 ` Linus Torvalds [this message]
2021-09-02 17:37 ` pr-tracker-bot

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='' \ \ \ \ \ \ \

* 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).