Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 3 Feb 2021 13:58:27 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Miklos Szeredi <miklos@szeredi.hu>
Cc:     Miklos Szeredi <mszeredi@redhat.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Al Viro <viro@zeniv.linux.org.uk>,
        Andreas Dilger <adilger@dilger.ca>,
        Andreas Gruenbacher <agruenba@redhat.com>,
        Christoph Hellwig <hch@lst.de>,
        "Darrick J . Wong" <djwong@kernel.org>,
        Dave Kleikamp <shaggy@kernel.org>,
        David Sterba <dsterba@suse.com>,
        Jaegeuk Kim <jaegeuk@kernel.org>, Jan Kara <jack@suse.cz>,
        Joel Becker <jlbec@evilplan.org>,
        Matthew Garrett <matthew.garrett@nebula.com>,
        Mike Marshall <hubcap@omnibond.com>,
        Richard Weinberger <richard@nod.at>,
        Ryusuke Konishi <konishi.ryusuke@gmail.com>,
        Theodore Ts'o <tytso@mit.edu>, Tyler Hicks <code@tyhicks.com>
Subject: Re: [PATCH 00/18] new API for FS_IOC_[GS]ETFLAGS/FS_IOC_FS[GS]ETXATTR
Message-ID: <20210203135827.GZ308988@casper.infradead.org>
References: <20210203124112.1182614-1-mszeredi@redhat.com>
 <20210203130501.GY308988@casper.infradead.org>
 <CAJfpegs3YWybmH7iKDLQ-KwmGieS1faO1uSZ-ADB0UFYOFPEnQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAJfpegs3YWybmH7iKDLQ-KwmGieS1faO1uSZ-ADB0UFYOFPEnQ@mail.gmail.com>
Precedence: bulk

On Wed, Feb 03, 2021 at 02:13:27PM +0100, Miklos Szeredi wrote:
> On Wed, Feb 3, 2021 at 2:08 PM Matthew Wilcox <willy@infradead.org> wrote:
> >
> > On Wed, Feb 03, 2021 at 01:40:54PM +0100, Miklos Szeredi wrote:
> > > This series adds the infrastructure and conversion of filesystems to the
> > > new API.
> > >
> > > Two filesystems are not converted: FUSE and CIFS, as they behave
> > > differently from local filesystems (use the file pointer, don't perform
> > > permission checks).  It's likely that these two can be supported with minor
> > > changes to the API, but this requires more thought.
> >
> > Why not change the API now?  ie pass the file instead of the dentry?
> 
> These are inode attributes we are talking about, not much sense in
> passing an open file to the filesystem.  That was/is due to ioctl
> being an fd based API.

You might as well say "Not much point passing a dentry to the filesystem"
and just pass the inode.

> It would make more sense to convert these filesystems to use a dentry
> instead of a file pointer.  Which is not trivial, unfortuantely.

Network filesystems frequently need to use the credentials attached to
a struct file in order to communicate with the server.  There's no point
fighting this reality.