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From: Chengguang Xu <cgxu519@mykernel.net>
To: "Miklos Szeredi" <miklos@szeredi.hu>
Cc: "overlayfs" <linux-unionfs@vger.kernel.org>
Subject: Re: [RFC PATCH 1/2] ovl: skip checking lower file's write permisson on truncate
Date: Wed, 21 Jul 2021 00:04:30 +0800	[thread overview]
Message-ID: <17ac4a9585a.fe9d56d860292.2175453677488603990@mykernel.net> (raw)
In-Reply-To: <CAJfpegvmMtXPg1qMznuimy27maqGxOtcddR-L0MUfAS6jwhE7Q@mail.gmail.com>

 ---- 在 星期三, 2021-07-21 00:01:11 Miklos Szeredi <miklos@szeredi.hu> 撰写 ----
 > On Tue, 20 Jul 2021 at 17:19, Miklos Szeredi <miklos@szeredi.hu> wrote:
 > 
 > > So on one instance a file on lower gets executed and on another
 > > instance sharing the lower layer the file is truncated.  The truncate
 > > is currently denied due to the negative i_writecount on the lower
 > > file.  Also behavior is inconsistent between open(path, O_TRUNC) and
 > > truncate(path) even though the two should be equivalent.
 > >
 > > Applied with the following description:
 > >
 > [...]
 > 
 > Also adding the following documentation in the "Non-standard behavior" section:
 > 
 > c) If a file residing on a lower layer is being executed, then opening that
 > file for write or truncating the file will not be denied with ETXTBSY.
 > 
 > Looked at the POSIX standard and it only documents ETXTBUSY for O_RDWR
 > and O_WRONLY and not for truncate(2) or O_TRUNC.  So strictly speaking
 > this patch doesn't even change the POSIX correctness.
 > 

Hi Miklos,

Thanks for doing this too.

Thanks,
Chengguang

      reply	other threads:[~2021-07-20 16:12 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-24 14:03 Chengguang Xu
2021-04-24 14:03 ` [RFC PATCH 2/2] ovl: enhance write permission check for writable open Chengguang Xu
2021-07-21 13:14   ` Miklos Szeredi
2021-04-28 12:18 ` 回复:[RFC PATCH 1/2] ovl: skip checking lower file's write permisson on truncate Chengguang Xu
2021-07-20 14:35 ` [RFC " Miklos Szeredi
2021-07-20 15:19   ` Miklos Szeredi
2021-07-20 16:01     ` Chengguang Xu
2021-07-20 16:01     ` Miklos Szeredi
2021-07-20 16:04       ` Chengguang Xu [this message]

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