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Date:   Mon, 8 Feb 2021 14:02:17 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Miklos Szeredi <miklos@szeredi.hu>
Cc:     Dave Chinner <david@fromorbit.com>,
        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>,
        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
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On Mon, Feb 08, 2021 at 09:25:22AM +0100, Miklos Szeredi wrote:
> On Mon, Feb 8, 2021 at 3:00 AM Dave Chinner <david@fromorbit.com> wrote:
> >
> > On Wed, Feb 03, 2021 at 04:03:06PM +0100, Miklos Szeredi wrote:
> > > On Wed, Feb 3, 2021 at 3:56 PM Matthew Wilcox <willy@infradead.org> wrote:
> > >
> > > > But let's talk specifics.  What does CIFS need to contact the server for?
> > > > Could it be cached earlier?
> > >
> > > I don't understand what CIFS is doing, and I don't really care.   This
> > > is the sort of operation where adding a couple of network roundtrips
> > > so that the client can obtain the credentials required to perform the
> > > operation doesn't really matter.  We won't have thousands of chattr(1)
> > > calls per second.
> >
> > Incorrect.
> 
> Okay, I was wrong.
> 
> Still, CIFS may very well be able to perform these operations without
> a struct file.   But even if it can't, I'd still only add the file
> pointer as an *optional hint* from the VFS, not as the primary object
> as Matthew suggested.
> 
> I stand by my choice of /struct dentry/ as the object to pass to these
> operations.

Why the dentry?  This is an inode operation.  Why doesn't it take an
inode as its primary object?