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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Aleksa Sarai <cyphar@cyphar.com>
Cc: David Howells <dhowells@redhat.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Stefan Metzmacher <metze@samba.org>, Ian Kent <raven@themaw.net>,
	Miklos Szeredi <mszeredi@redhat.com>,
	Christian Brauner <christian@brauner.io>,
	Jann Horn <jannh@google.com>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	Karel Zak <kzak@redhat.com>,
	jlayton@redhat.com, Linux API <linux-api@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	LSM List <linux-security-module@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 01/14] VFS: Add additional RESOLVE_* flags [ver #18]
Date: Mon, 9 Mar 2020 18:14:00 -0700	[thread overview]
Message-ID: <CAHk-=wiEBNFJ0_riJnpuUXTO7+_HByVo-R3pGoB_84qv3LzHxA@mail.gmail.com> (raw)
In-Reply-To: <20200310005549.adrn3yf4mbljc5f6@yavin>

On Mon, Mar 9, 2020 at 5:56 PM Aleksa Sarai <cyphar@cyphar.com> wrote:
>
> On 2020-03-09, David Howells <dhowells@redhat.com> wrote:
> > This is necessary for fsinfo() to use RESOLVE_* flags instead of AT_* flags
> > if the latter are to be considered deprecated for new system calls.
> >
> > Also make openat2() handle RESOLVE_NO_TRAILING_SYMLINKS.

No, please let's not do this.

We have O_NOFOLLOW, and we can't get rid of it.

So adding RESOLVE_NO_TRAILING_SYMLINKS isn't a cleanup. It's just
extra complexity for absolutely zero gain.


> After thinking about what Christian said some more, I reckon we
> shouldn't support both O_NOFOLLOW and RESOLVE_NO_TRAILING_SYMLINKS. But
> that means we'll need to cherry-pick this patch and get it into mainline
> before v5.6.

No.

It simply means that we shouldn't have RESOLVE_NO_TRAILING_SYMLINKS at all.

Adding that flag is a mistake. It causes problems like this, where
subtlenly people say "what if both flags are set".

Just don't do it.

There's no way in hell we can ever get rid of O_NOFOLLOW anyway, since
people will continue to use plain open() and openat().

So adding RESOLVE_NO_TRAILING_SYMLINKS is entirely redundant.

Don't deprecate the old flags that are going to always stay around,
don't add stupid new flags that add no value.

It's that easy.

              Linus

  parent reply	other threads:[~2020-03-10  1:14 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-09 14:00 [PATCH 00/14] VFS: Filesystem information [ver #18] David Howells
2020-03-09 14:00 ` [PATCH 01/14] VFS: Add additional RESOLVE_* flags " David Howells
2020-03-09 20:56   ` Stefan Metzmacher
2020-03-09 21:13   ` David Howells
     [not found]   ` <20200310005549.adrn3yf4mbljc5f6@yavin>
2020-03-10  1:14     ` Linus Torvalds [this message]
2020-03-10  7:25     ` David Howells
2020-03-11 17:59       ` Linus Torvalds
2020-03-12  9:08         ` Stefan Metzmacher
2020-03-12 16:24           ` Linus Torvalds
2020-03-12 17:11             ` Stefan Metzmacher
2020-03-12 19:37               ` Al Viro
2020-03-12 21:48               ` Jeremy Allison
     [not found]               ` <20200313095901.tdv4vl7envypgqfz@yavin>
2020-03-13 16:48                 ` Jeremy Allison
2020-03-13 18:28                 ` Al Viro
2020-03-13 18:35                   ` Jeremy Allison
2020-03-16 14:20                   ` Aleksa Sarai
2020-03-12 19:25             ` Al Viro
2020-03-12 16:56           ` David Howells
2020-03-12 18:09             ` Linus Torvalds
2020-03-09 14:01 ` [PATCH 02/14] fsinfo: Add fsinfo() syscall to query filesystem information " David Howells
2020-03-10  9:31   ` Christian Brauner
2020-03-10  9:32     ` [PATCH v19 01/14] fsinfo: Add fsinfo() syscall to query filesystem information Christian Brauner
2020-03-10  9:32       ` [PATCH v19 14/14] arch: wire up fsinfo syscall Christian Brauner
2020-03-09 14:01 ` [PATCH 03/14] fsinfo: Provide a bitmap of supported features [ver #18] David Howells
2020-03-09 14:01 ` [PATCH 04/14] fsinfo: Allow retrieval of superblock devname, options and stats " David Howells
2020-03-09 14:01 ` [PATCH 05/14] fsinfo: Allow fsinfo() to look up a mount object by ID " David Howells
2020-03-09 14:01 ` [PATCH 06/14] fsinfo: Add a uniquifier ID to struct mount " David Howells
2020-03-09 14:01 ` [PATCH 07/14] fsinfo: Allow mount information to be queried " David Howells
2020-03-10  9:04   ` Miklos Szeredi
2020-03-09 14:02 ` [PATCH 08/14] fsinfo: Allow the mount topology propogation flags to be retrieved " David Howells
2020-03-10  8:42   ` Christian Brauner
2020-03-09 14:02 ` [PATCH 09/14] fsinfo: Provide notification overrun handling support " David Howells
2020-03-09 14:02 ` [PATCH 10/14] fsinfo: sample: Mount listing program " David Howells
2020-03-09 14:02 ` [PATCH 11/14] fsinfo: Add API documentation " David Howells
2020-03-09 14:02 ` [PATCH 12/14] fsinfo: Add support for AFS " David Howells
2020-03-09 14:02 ` [PATCH 13/14] fsinfo: Example support for Ext4 " David Howells
2020-03-09 14:02 ` [PATCH 14/14] fsinfo: Example support for NFS " David Howells
2020-03-09 17:50 ` [PATCH 00/14] VFS: Filesystem information " Jeff Layton
2020-03-09 19:22   ` Andres Freund
2020-03-09 22:49     ` Jeff Layton
2020-03-10  0:18       ` Andres Freund
2020-03-09 20:02 ` Miklos Szeredi
2020-03-09 22:52 ` David Howells
2020-03-10  9:18   ` Miklos Szeredi

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