Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20221024173140.30673-1-ivan@cloudflare.com> <Y3fYu2VCBgREBBau@bfoster>
In-Reply-To: <Y3fYu2VCBgREBBau@bfoster>
From:   Ivan Babrou <ivan@cloudflare.com>
Date:   Fri, 18 Nov 2022 11:18:36 -0800
Message-ID: <CABWYdi3csS3BpoMd8xO=ZXFeBH7KtuLkxzQ8VE5+rO5wrx-yQQ@mail.gmail.com>
Subject: Re: [PATCH v4] proc: report open files as size in stat() for /proc/pid/fd
To:     Brian Foster <bfoster@redhat.com>
Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        kernel-team@cloudflare.com, Alexey Dobriyan <adobriyan@gmail.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        "Theodore Ts'o" <tytso@mit.edu>,
        David Laight <David.Laight@aculab.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Hildenbrand <david@redhat.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Christoph Anton Mitterer <mail@christoph.anton.mitterer.name>,
        Mike Rapoport <rppt@kernel.org>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Kalesh Singh <kaleshsingh@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, Nov 18, 2022 at 11:10 AM Brian Foster <bfoster@redhat.com> wrote:
> > +static int proc_fd_getattr(struct user_namespace *mnt_userns,
> > +                     const struct path *path, struct kstat *stat,
> > +                     u32 request_mask, unsigned int query_flags)
> > +{
> > +     struct inode *inode = d_inode(path->dentry);
> > +     int rv = 0;
> > +
> > +     generic_fillattr(&init_user_ns, inode, stat);
> > +
>
> Sorry I missed this on v3, but shouldn't this pass through the
> mnt_userns parameter?

The mnt_userns parameter was added in 549c729 (fs: make helpers idmap
mount aware), and it's not passed anywhere in fs/proc.

Looking at other uses of generic_fillattr, all of them use "init_user_ns":

$ rg generic_fillattr fs/proc
fs/proc/proc_net.c
301: generic_fillattr(&init_user_ns, inode, stat);

fs/proc/base.c
1970: generic_fillattr(&init_user_ns, inode, stat);
3856: generic_fillattr(&init_user_ns, inode, stat);

fs/proc/root.c
315: generic_fillattr(&init_user_ns, d_inode(path->dentry), stat);

fs/proc/generic.c
150: generic_fillattr(&init_user_ns, inode, stat);

fs/proc/proc_sysctl.c
841: generic_fillattr(&init_user_ns, inode, stat);