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From: "Jörn Engel" <joern@logfs.org>
To: Joel Becker <Joel.Becker@oracle.com>
Cc: jim owens <jowens@hp.com>,
	jmorris@namei.org, ocfs2-devel@oss.oracle.com,
	viro@zeniv.linux.org.uk, mtk.manpages@gmail.com,
	linux-security-module@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Subject: Re: [RFC] The reflink(2) system call v4.
Date: Tue, 12 May 2009 13:31:52 +0200	[thread overview]
Message-ID: <20090512113152.GE6585@logfs.org> (raw)
In-Reply-To: <20090511204011.GB30293@mail.oracle.com>

On Mon, 11 May 2009 13:40:11 -0700, Joel Becker wrote:
>
> 	Here's v4 of reflink().  If you have the privileges, you get the
> full snapshot.  If you don't, you must have read access, and then you
> get the entire snapshot (data and extended attributes) except that the
> security context is reinitialized.  That's it.  It fits with most of the
> other ops, and it's a clean degradation.

Let me see if I understand this correctly.  File "/tmp/foo" belongs to
Joel, file "/tmp/bar" belongs to Joern.  Everyone has read access to
those files.  Now if you reflink them to your home directory, both files
belong to you.  If I reflink them to my home directory, both files
belong to me.  And if root reflinks them to /root, one file belongs to
Joel, the other to Joern.  Is that correct?

Because if it is, I would call that behaviour rather confusing.  A
system call that behaves differently depending on who calls it - or
on whether the binary is installed suid root - is something I would like
to avoid.

Jörn

-- 
A surrounded army must be given a way out.
-- Sun Tzu
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WARNING: multiple messages have this Message-ID (diff)
From: "Jörn Engel" <joern@logfs.org>
To: Joel Becker <Joel.Becker@oracle.com>
Cc: jim owens <jowens@hp.com>,
	jmorris@namei.org, ocfs2-devel@oss.oracle.com,
	viro@zeniv.linux.org.uk, mtk.manpages@gmail.com,
	linux-security-module@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Subject: [Ocfs2-devel] [RFC] The reflink(2) system call v4.
Date: Tue, 12 May 2009 13:31:52 +0200	[thread overview]
Message-ID: <20090512113152.GE6585@logfs.org> (raw)
In-Reply-To: <20090511204011.GB30293@mail.oracle.com>

On Mon, 11 May 2009 13:40:11 -0700, Joel Becker wrote:
>
> 	Here's v4 of reflink().  If you have the privileges, you get the
> full snapshot.  If you don't, you must have read access, and then you
> get the entire snapshot (data and extended attributes) except that the
> security context is reinitialized.  That's it.  It fits with most of the
> other ops, and it's a clean degradation.

Let me see if I understand this correctly.  File "/tmp/foo" belongs to
Joel, file "/tmp/bar" belongs to Joern.  Everyone has read access to
those files.  Now if you reflink them to your home directory, both files
belong to you.  If I reflink them to my home directory, both files
belong to me.  And if root reflinks them to /root, one file belongs to
Joel, the other to Joern.  Is that correct?

Because if it is, I would call that behaviour rather confusing.  A
system call that behaves differently depending on who calls it - or
on whether the binary is installed suid root - is something I would like
to avoid.

J?rn

-- 
A surrounded army must be given a way out.
-- Sun Tzu

  parent reply	other threads:[~2009-05-12 11:32 UTC|newest]

Thread overview: 304+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-03  6:15 [RFC] The reflink(2) system call Joel Becker
2009-05-03  6:15 ` [Ocfs2-devel] " Joel Becker
2009-05-03  6:15 ` [PATCH 1/3] fs: Document the " Joel Becker
2009-05-03  6:15   ` [Ocfs2-devel] " Joel Becker
2009-05-03  8:01   ` Christoph Hellwig
2009-05-03  8:01     ` [Ocfs2-devel] " Christoph Hellwig
2009-05-04  2:46     ` Joel Becker
2009-05-04  2:46       ` [Ocfs2-devel] " Joel Becker
2009-05-04  6:36       ` Michael Kerrisk
2009-05-04  6:36         ` [Ocfs2-devel] " Michael Kerrisk
2009-05-04  7:12         ` Joel Becker
2009-05-04  7:12           ` [Ocfs2-devel] " Joel Becker
2009-05-03 13:08   ` Boaz Harrosh
2009-05-03 13:08     ` [Ocfs2-devel] " Boaz Harrosh
2009-05-03 23:08     ` Al Viro
2009-05-03 23:08       ` [Ocfs2-devel] " Al Viro
2009-05-04  2:49     ` Joel Becker
2009-05-04  2:49       ` [Ocfs2-devel] " Joel Becker
2009-05-03 23:45   ` Theodore Tso
2009-05-03 23:45     ` [Ocfs2-devel] " Theodore Tso
2009-05-04  1:44     ` Tao Ma
2009-05-04  1:44       ` [Ocfs2-devel] " Tao Ma
2009-05-04 18:25       ` Joel Becker
2009-05-04 18:25         ` [Ocfs2-devel] " Joel Becker
2009-05-04 21:18         ` Joel Becker
2009-05-04 21:18           ` Joel Becker
2009-05-04 22:23           ` Theodore Tso
2009-05-04 22:23             ` Theodore Tso
2009-05-05  6:55             ` Joel Becker
2009-05-05  6:55               ` Joel Becker
2009-05-05  1:07   ` Jamie Lokier
2009-05-05  1:07     ` [Ocfs2-devel] " Jamie Lokier
2009-05-05  7:16     ` Joel Becker
2009-05-05  7:16       ` [Ocfs2-devel] " Joel Becker
2009-05-05  8:09       ` Andreas Dilger
2009-05-05  8:09         ` [Ocfs2-devel] " Andreas Dilger
2009-05-05 16:56         ` Joel Becker
2009-05-05 16:56           ` [Ocfs2-devel] " Joel Becker
2009-05-05 21:24           ` Andreas Dilger
2009-05-05 21:24             ` [Ocfs2-devel] " Andreas Dilger
2009-05-05 21:32             ` Joel Becker
2009-05-05 21:32               ` [Ocfs2-devel] " Joel Becker
2009-05-06  7:15               ` Theodore Tso
2009-05-06  7:15                 ` Theodore Tso
2009-05-06 14:24                 ` jim owens
2009-05-06 14:24                   ` jim owens
2009-05-06 14:30                   ` jim owens
2009-05-06 14:30                     ` jim owens
2009-05-06 17:50                     ` jim owens
2009-05-06 17:50                       ` jim owens
2009-05-12 19:20                       ` Jamie Lokier
2009-05-12 19:20                         ` Jamie Lokier
2009-05-12 19:30                       ` Jamie Lokier
2009-05-12 19:30                         ` Jamie Lokier
2009-05-12 19:11                   ` Jamie Lokier
2009-05-12 19:11                     ` Jamie Lokier
2009-05-12 19:37                     ` jim owens
2009-05-12 19:37                       ` jim owens
2009-05-12 20:11                       ` Jamie Lokier
2009-05-12 20:11                         ` Jamie Lokier
2009-05-05 13:01       ` Theodore Tso
2009-05-05 13:01         ` [Ocfs2-devel] " Theodore Tso
2009-05-05 13:19         ` Jamie Lokier
2009-05-05 13:19           ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 13:39           ` Chris Mason
2009-05-05 13:39             ` [Ocfs2-devel] " Chris Mason
2009-05-05 15:36             ` Jamie Lokier
2009-05-05 15:36               ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 15:41               ` Chris Mason
2009-05-05 15:41                 ` [Ocfs2-devel] " Chris Mason
2009-05-05 16:03                 ` Jamie Lokier
2009-05-05 16:03                   ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 16:18                   ` Chris Mason
2009-05-05 16:18                     ` [Ocfs2-devel] " Chris Mason
2009-05-05 20:48                   ` jim owens
2009-05-05 20:48                     ` [Ocfs2-devel] " jim owens
2009-05-05 21:57                     ` Jamie Lokier
2009-05-05 21:57                       ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 22:04                       ` Joel Becker
2009-05-05 22:04                         ` [Ocfs2-devel] " Joel Becker
2009-05-05 22:11                         ` Jamie Lokier
2009-05-05 22:11                           ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 22:24                           ` Joel Becker
2009-05-05 22:24                             ` [Ocfs2-devel] " Joel Becker
2009-05-05 23:14                             ` Jamie Lokier
2009-05-05 23:14                               ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 22:12                         ` Jamie Lokier
2009-05-05 22:12                           ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 22:21                           ` Joel Becker
2009-05-05 22:21                             ` [Ocfs2-devel] " Joel Becker
2009-05-05 22:32                             ` James Morris
2009-05-05 22:32                               ` [Ocfs2-devel] " James Morris
2009-05-05 22:39                               ` Joel Becker
2009-05-05 22:39                                 ` [Ocfs2-devel] " Joel Becker
2009-05-12 19:40                               ` Jamie Lokier
2009-05-12 19:40                                 ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 22:28                         ` jim owens
2009-05-05 22:28                           ` [Ocfs2-devel] " jim owens
2009-05-05 23:12                           ` Jamie Lokier
2009-05-05 23:12                             ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 16:46               ` Jörn Engel
2009-05-05 16:46                 ` [Ocfs2-devel] " Jörn Engel
2009-05-05 16:54                 ` Jörn Engel
2009-05-05 16:54                   ` [Ocfs2-devel] " Jörn Engel
2009-05-05 22:03                   ` Jamie Lokier
2009-05-05 22:03                     ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 21:44                 ` copyfile semantics Andreas Dilger
2009-05-05 21:44                   ` [Ocfs2-devel] " Andreas Dilger
2009-05-05 21:48                   ` Matthew Wilcox
2009-05-05 21:48                     ` [Ocfs2-devel] " Matthew Wilcox
2009-05-05 22:25                     ` Trond Myklebust
2009-05-05 22:25                       ` [Ocfs2-devel] " Trond Myklebust
2009-05-05 22:06                   ` Jamie Lokier
2009-05-05 22:06                     ` [Ocfs2-devel] " Jamie Lokier
2009-05-06  5:57                   ` Jörn Engel
2009-05-06  5:57                     ` [Ocfs2-devel] " Jörn Engel
2009-05-05 14:21           ` [PATCH 1/3] fs: Document the reflink(2) system call Theodore Tso
2009-05-05 14:21             ` [Ocfs2-devel] " Theodore Tso
2009-05-05 15:32             ` Jamie Lokier
2009-05-05 15:32               ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 22:49             ` James Morris
2009-05-05 22:49               ` [Ocfs2-devel] " James Morris
2009-05-05 17:05           ` Joel Becker
2009-05-05 17:05             ` [Ocfs2-devel] " Joel Becker
2009-05-05 17:00         ` Joel Becker
2009-05-05 17:00           ` [Ocfs2-devel] " Joel Becker
2009-05-05 17:29           ` Theodore Tso
2009-05-05 17:29             ` [Ocfs2-devel] " Theodore Tso
2009-05-05 22:36             ` Jamie Lokier
2009-05-05 22:36               ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 22:30           ` Jamie Lokier
2009-05-05 22:30             ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 22:37             ` Joel Becker
2009-05-05 22:37               ` [Ocfs2-devel] " Joel Becker
2009-05-05 23:08             ` jim owens
2009-05-05 23:08               ` [Ocfs2-devel] " jim owens
2009-05-05 13:01       ` Jamie Lokier
2009-05-05 13:01         ` [Ocfs2-devel] " Jamie Lokier
2009-05-05 17:09         ` Joel Becker
2009-05-05 17:09           ` [Ocfs2-devel] " Joel Becker
2009-05-03  6:15 ` [PATCH 2/3] fs: Add vfs_reflink() and the ->reflink() inode operation Joel Becker
2009-05-03  6:15   ` [Ocfs2-devel] " Joel Becker
2009-05-03  8:03   ` Christoph Hellwig
2009-05-03  8:03     ` [Ocfs2-devel] " Christoph Hellwig
2009-05-04  2:51     ` Joel Becker
2009-05-04  2:51       ` [Ocfs2-devel] " Joel Becker
2009-05-03  6:15 ` [PATCH 3/3] fs: Add the reflink(2) system call Joel Becker
2009-05-03  6:15   ` [Ocfs2-devel] " Joel Becker
2009-05-03  6:27   ` Matthew Wilcox
2009-05-03  6:27     ` [Ocfs2-devel] " Matthew Wilcox
2009-05-03  6:39     ` Al Viro
2009-05-03  6:39       ` [Ocfs2-devel] " Al Viro
2009-05-03  7:48       ` Christoph Hellwig
2009-05-03  7:48         ` [Ocfs2-devel] " Christoph Hellwig
2009-05-03 11:16         ` Al Viro
2009-05-03 11:16           ` [Ocfs2-devel] " Al Viro
2009-05-04  2:53       ` Joel Becker
2009-05-04  2:53         ` [Ocfs2-devel] " Joel Becker
2009-05-04  2:53     ` Joel Becker
2009-05-04  2:53       ` [Ocfs2-devel] " Joel Becker
2009-05-03  8:04   ` Christoph Hellwig
2009-05-03  8:04     ` [Ocfs2-devel] " Christoph Hellwig
2009-05-07 22:15 ` [RFC] The reflink(2) system call v2 Joel Becker
2009-05-07 22:15   ` [Ocfs2-devel] " Joel Becker
2009-05-08  1:39   ` James Morris
2009-05-08  1:39     ` [Ocfs2-devel] " James Morris
2009-05-08  1:49     ` Joel Becker
2009-05-08  1:49       ` [Ocfs2-devel] " Joel Becker
2009-05-08 13:01       ` Tetsuo Handa
2009-05-08  2:59   ` jim owens
2009-05-08  2:59     ` [Ocfs2-devel] " jim owens
2009-05-08  3:10     ` Joel Becker
2009-05-08  3:10       ` [Ocfs2-devel] " Joel Becker
2009-05-08 11:53       ` jim owens
2009-05-08 11:53         ` [Ocfs2-devel] " jim owens
2009-05-08 12:16       ` jim owens
2009-05-08 12:16         ` [Ocfs2-devel] " jim owens
2009-05-08 14:11         ` jim owens
2009-05-08 14:11           ` [Ocfs2-devel] " jim owens
2009-05-11 20:40       ` [RFC] The reflink(2) system call v4 Joel Becker
2009-05-11 20:40         ` [Ocfs2-devel] " Joel Becker
2009-05-11 22:27         ` James Morris
2009-05-11 22:27           ` [Ocfs2-devel] " James Morris
2009-05-11 22:34           ` Joel Becker
2009-05-11 22:34             ` [Ocfs2-devel] " Joel Becker
2009-05-12  1:12             ` James Morris
2009-05-12  1:12               ` [Ocfs2-devel] " James Morris
2009-05-12 12:18               ` Stephen Smalley
2009-05-12 12:18                 ` [Ocfs2-devel] " Stephen Smalley
2009-05-12 17:22                 ` Joel Becker
2009-05-12 17:22                   ` [Ocfs2-devel] " Joel Becker
2009-05-12 17:32                   ` Stephen Smalley
2009-05-12 17:32                     ` [Ocfs2-devel] " Stephen Smalley
2009-05-12 18:03                     ` Joel Becker
2009-05-12 18:03                       ` [Ocfs2-devel] " Joel Becker
2009-05-12 18:04                       ` Stephen Smalley
2009-05-12 18:04                         ` [Ocfs2-devel] " Stephen Smalley
2009-05-12 18:28                         ` Joel Becker
2009-05-12 18:28                           ` [Ocfs2-devel] " Joel Becker
2009-05-12 18:37                           ` Stephen Smalley
2009-05-12 18:37                             ` [Ocfs2-devel] " Stephen Smalley
2009-05-14 18:06                         ` Stephen Smalley
2009-05-14 18:06                           ` [Ocfs2-devel] " Stephen Smalley
2009-05-14 18:25                           ` Stephen Smalley
2009-05-14 18:25                             ` [Ocfs2-devel] " Stephen Smalley
2009-05-14 23:25                             ` James Morris
2009-05-14 23:25                               ` [Ocfs2-devel] " James Morris
2009-05-15 11:54                               ` Stephen Smalley
2009-05-15 11:54                                 ` [Ocfs2-devel] " Stephen Smalley
2009-05-15 13:35                                 ` James Morris
2009-05-15 13:35                                   ` [Ocfs2-devel] " James Morris
2009-05-15 15:44                                   ` Stephen Smalley
2009-05-15 15:44                                     ` [Ocfs2-devel] " Stephen Smalley
2009-05-13  1:47                       ` Casey Schaufler
2009-05-13  1:47                         ` [Ocfs2-devel] " Casey Schaufler
2009-05-13 16:43                         ` Joel Becker
2009-05-13 16:43                           ` [Ocfs2-devel] " Joel Becker
2009-05-13 17:23                           ` Stephen Smalley
2009-05-13 17:23                             ` [Ocfs2-devel] " Stephen Smalley
2009-05-13 18:27                             ` Joel Becker
2009-05-13 18:27                               ` [Ocfs2-devel] " Joel Becker
2009-05-12 12:01           ` Stephen Smalley
2009-05-12 12:01             ` [Ocfs2-devel] " Stephen Smalley
2009-05-11 23:11         ` jim owens
2009-05-11 23:11           ` [Ocfs2-devel] " jim owens
2009-05-11 23:42           ` Joel Becker
2009-05-11 23:42             ` [Ocfs2-devel] " Joel Becker
2009-05-12 11:31         ` Jörn Engel [this message]
2009-05-12 11:31           ` Jörn Engel
2009-05-12 13:12           ` jim owens
2009-05-12 13:12             ` [Ocfs2-devel] " jim owens
2009-05-12 20:24             ` Jamie Lokier
2009-05-12 20:24               ` [Ocfs2-devel] " Jamie Lokier
2009-05-14 18:43             ` Jörn Engel
2009-05-14 18:43               ` [Ocfs2-devel] " Jörn Engel
2009-05-12 15:04         ` Sage Weil
2009-05-12 15:04           ` [Ocfs2-devel] " Sage Weil
2009-05-12 15:23           ` jim owens
2009-05-12 15:23             ` [Ocfs2-devel] " jim owens
2009-05-12 16:16             ` Sage Weil
2009-05-12 16:16               ` [Ocfs2-devel] " Sage Weil
2009-05-12 17:45               ` jim owens
2009-05-12 17:45                 ` [Ocfs2-devel] " jim owens
2009-05-12 20:29                 ` Jamie Lokier
2009-05-12 20:29                   ` [Ocfs2-devel] " Jamie Lokier
2009-05-12 17:28           ` Joel Becker
2009-05-12 17:28             ` [Ocfs2-devel] " Joel Becker
2009-05-13  4:30             ` Sage Weil
2009-05-13  4:30               ` [Ocfs2-devel] " Sage Weil
2009-05-14  3:57         ` Andy Lutomirski
2009-05-14  3:57           ` [Ocfs2-devel] " Andy Lutomirski
2009-05-14 18:12           ` Stephen Smalley
2009-05-14 18:12             ` [Ocfs2-devel] " Stephen Smalley
2009-05-14 22:00             ` Joel Becker
2009-05-14 22:00               ` [Ocfs2-devel] " Joel Becker
2009-05-15  1:20               ` Jamie Lokier
2009-05-15  1:20               ` [Ocfs2-devel] " Jamie Lokier
2009-05-15 12:01               ` Stephen Smalley
2009-05-15 12:01                 ` [Ocfs2-devel] " Stephen Smalley
2009-05-15 15:22                 ` Joel Becker
2009-05-15 15:22                   ` [Ocfs2-devel] " Joel Becker
2009-05-15 15:55                   ` Stephen Smalley
2009-05-15 15:55                     ` [Ocfs2-devel] " Stephen Smalley
2009-05-15 16:42                     ` Joel Becker
2009-05-15 16:42                       ` [Ocfs2-devel] " Joel Becker
2009-05-15 17:01                       ` Shaya Potter
2009-05-15 17:01                       ` Shaya Potter
2009-05-15 20:53                       ` [Ocfs2-devel] " Joel Becker
2009-05-15 20:53                         ` Joel Becker
2009-05-18  9:17                         ` Jörn Engel
2009-05-18  9:17                           ` Jörn Engel
2009-05-18 13:02                         ` Stephen Smalley
2009-05-18 13:02                           ` Stephen Smalley
2009-05-18 14:33                           ` Stephen Smalley
2009-05-18 14:33                             ` Stephen Smalley
2009-05-18 17:15                             ` Stephen Smalley
2009-05-18 17:15                               ` Stephen Smalley
2009-05-18 18:26                           ` Joel Becker
2009-05-18 18:26                             ` [Ocfs2-devel] " Joel Becker
2009-05-19 16:32                             ` Sage Weil
2009-05-19 16:32                               ` Sage Weil
2009-05-19 19:20                         ` Jonathan Corbet
2009-05-19 19:32                           ` Joel Becker
2009-05-19 19:41                             ` Jonathan Corbet
2009-05-19 19:41                               ` Jonathan Corbet
2009-05-19 19:33                         ` Jonathan Corbet
2009-05-19 20:15                           ` Jamie Lokier
2009-05-25  7:44         ` [Ocfs2-devel] [RFC] The reflink(2) system call v4. - Question for suitability Mihail Daskalov
2009-05-25 20:42           ` Joel Becker
2009-05-28  0:24         ` [Ocfs2-devel] [RFC] The reflink(2) system call v5 Joel Becker
2009-05-28  0:24         ` Joel Becker
2009-09-14 22:24         ` Joel Becker
2009-09-14 22:24         ` Joel Becker
2009-09-14 22:24           ` [Ocfs2-devel] " Joel Becker
2009-05-11 20:49     ` [RFC] The reflink(2) system call v2 Joel Becker
2009-05-11 20:49       ` [Ocfs2-devel] " Joel Becker
2009-05-11 22:49       ` jim owens
2009-05-11 22:49         ` [Ocfs2-devel] " jim owens
2009-05-11 23:46         ` Joel Becker
2009-05-11 23:46           ` [Ocfs2-devel] " Joel Becker
2009-05-12  0:54           ` Chris Mason
2009-05-12  0:54             ` [Ocfs2-devel] " Chris Mason
2009-05-12 20:36           ` Jamie Lokier
2009-05-12 20:36             ` [Ocfs2-devel] " Jamie Lokier

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