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Date:   Sat, 30 Jul 2022 01:15:45 +0100
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Oleg Nesterov <oleg@redhat.com>
Cc:     "Eric W. Biederman" <ebiederm@xmission.com>,
        Tycho Andersen <tycho@tycho.pizza>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Miklos Szeredi <miklos@szeredi.hu>,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [RFC][PATCH] fuse: In fuse_flush only wait if someone wants the
 return code
Message-ID: <YuR4MRL8WxA88il+@ZenIV>
References: <20220727191949.GD18822@redhat.com>
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 <20220729204730.GA3625@redhat.com>
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On Fri, Jul 29, 2022 at 10:47:32PM +0200, Oleg Nesterov wrote:
> On 07/29, Eric W. Biederman wrote:
> >
> > +static int fuse_flush_async(struct file *file, fl_owner_t id)
> > +{
> > +	struct inode *inode = file_inode(file);
> > +	struct fuse_mount *fm = get_fuse_mount(inode);
> > +	struct fuse_file *ff = file->private_data;
> > +	struct fuse_flush_args *fa;
> > +	int err;
> > +
> > +	fa = kzalloc(sizeof(*fa), GFP_KERNEL);
> > +	if (!fa)
> > +		return -ENOMEM;
> > +
> > +	fa->inarg.fh = ff->fh;
> > +	fa->inarg.lock_owner = fuse_lock_owner_id(fm->fc, id);
> > +	fa->args.opcode = FUSE_FLUSH;
> > +	fa->args.nodeid = get_node_id(inode);
> > +	fa->args.in_numargs = 1;
> > +	fa->args.in_args[0].size = sizeof(fa->inarg);
> > +	fa->args.in_args[0].value = &fa->inarg;
> > +	fa->args.force = true;
> > +	fa->args.end = fuse_flush_end;
> > +	fa->inode = inode;
> > +	__iget(inode);
> 
> Hmm... who does iput() ?

... or holds ->i_lock as expected by __iget()...