linux-kernel - Re: [RFC PATCH 0/2] vfs:9p: fix open-unlink-fstat bug

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Message-ID: <20200720015212.GN2786714@ZenIV.linux.org.uk>
Date:   Mon, 20 Jul 2020 02:52:12 +0100
From:   Al Viro <viro@...iv.linux.org.uk>
To:     Jianyong Wu <jianyong.wu@....com>
Cc:     ericvh@...il.com, hch@....de, dhowells@...hat.com,
        lucho@...kov.net, asmadeus@...ewreck.org,
        v9fs-developer@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
        Kaly.Xin@....com, justin.he@....com, wei.chen@....com
Subject: Re: [RFC PATCH 0/2] vfs:9p: fix open-unlink-fstat bug

On Mon, Jul 20, 2020 at 09:46:20AM +0800, Jianyong Wu wrote:
> how to reproduce:
> in 9p guest:
> 
> struct stat *statbuf;
> int fd;
> 
> fd = open("tmp", O_RDWR);
> unlink("tmp");
> fstat(fd, statbuf);
> 
> fstat will fail as "tmp" in 9p server side has been removed. 9p server
> can't retrieve the file context as the guest has not passed it down.
> so we should pass the file info down in 9p guest in getattr op.
> it need add a new file member in "struct kstat" as "struct istat" does.

Er... what struct istat?