From: Theodore Tso <tytso@MIT.EDU>
To: Kay Sievers <kay.sievers@vrfy.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org, lennart@poettering.net,
harald@redhat.com, david@fubar.dk, greg@kroah.com
Subject: Re: A Plumber’s Wish List for Linux
Date: Fri, 7 Oct 2011 09:39:49 -0400 [thread overview]
Message-ID: <8E8162FF-C301-40C1-9FBC-9B6ADB29BC59@mit.edu> (raw)
In-Reply-To: <CAPXgP11K4_eVn4_emEYVzCVUsm-BXDyStk7DnDmFpMTL=404Gg@mail.gmail.com>
On Oct 7, 2011, at 8:46 AM, Kay Sievers wrote:
> On Fri, Oct 7, 2011 at 12:38, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>> On Fri, 7 Oct 2011 12:28:46 +0200 Kay Sievers <kay.sievers@vrfy.org> wrote:
>>> What do you mean would be ugly?
>>
>> I have an ext4fs. It supports every possible file name allowed by POSIX
>> and SuS. What name are you going to use for your 'hidden directory' that
>> won't clash with a real file ?
>
> Ah, no. The label on FAT (similar on NTFS) are 'magic entries' in the
> root dir list, not a real file in the root dir.
>
> We need kernel support for changing a mounted fs, because, unlike
> ext4, the blocks containing the strings are inside the fs, which the
> kernel might change any time.
I'd suggest a syscall, not an ioctl, and if a file system has some limitation on what is a valid name (even ext4 has length limitations which might be different from other file systems), we just simply return an error if it's not a valid label name.
As it turns out I went to great lengths in both the kernel and userspace implementations of e2label/tune2fs to make sure it would be safe to directly edit the superblock while the file system is mounted, but that depends on implementation details of the buffer cache in the kernel. Better to have a formally supported interface which is file system independent.
-- Ted
next prev parent reply other threads:[~2011-10-07 13:39 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-06 23:17 Kay Sievers
2011-10-06 23:46 ` Andi Kleen
2011-10-07 0:13 ` Lennart Poettering
2011-10-07 1:57 ` Andi Kleen
2011-10-07 15:58 ` Lennart Poettering
2011-10-19 23:16 ` H. Peter Anvin
2011-10-07 7:49 ` Matt Helsley
2011-10-07 16:01 ` Lennart Poettering
2011-10-08 4:24 ` Eric W. Biederman
2011-10-10 16:31 ` Lennart Poettering
2011-10-10 20:59 ` Detecting if you are running in a container Eric W. Biederman
2011-10-10 21:41 ` Lennart Poettering
2011-10-11 5:40 ` Eric W. Biederman
2011-10-11 6:54 ` Eric W. Biederman
2011-10-12 16:59 ` Kay Sievers
2011-11-01 22:05 ` [lxc-devel] " Michael Tokarev
2011-11-01 23:51 ` Eric W. Biederman
2011-11-02 8:08 ` Michael Tokarev
2011-10-11 1:32 ` Ted Ts'o
2011-10-11 2:05 ` Matt Helsley
2011-10-11 3:25 ` Ted Ts'o
2011-10-11 6:42 ` Eric W. Biederman
2011-10-11 12:53 ` Theodore Tso
2011-10-11 21:16 ` Eric W. Biederman
2011-10-11 22:30 ` david
2011-10-12 4:26 ` Eric W. Biederman
2011-10-12 5:10 ` david
2011-10-12 15:08 ` Serge E. Hallyn
2011-10-12 17:57 ` J. Bruce Fields
2011-10-12 18:25 ` Kyle Moffett
2011-10-12 19:04 ` J. Bruce Fields
2011-10-12 19:12 ` Kyle Moffett
2011-10-14 15:54 ` Ted Ts'o
2011-10-14 18:04 ` Eric W. Biederman
2011-10-14 21:58 ` H. Peter Anvin
2011-10-16 9:42 ` Eric W. Biederman
2011-10-30 20:11 ` H. Peter Anvin
2011-11-01 13:38 ` Eric W. Biederman
2011-10-11 22:25 ` david
2011-10-07 10:12 ` A Plumber’s Wish List for Linux Alan Cox
2011-10-07 10:28 ` Kay Sievers
2011-10-07 10:38 ` Alan Cox
2011-10-07 12:46 ` Kay Sievers
2011-10-07 13:39 ` Theodore Tso [this message]
2011-10-07 15:21 ` Hugo Mills
2011-10-10 11:18 ` A Plumber???s " David Sterba
2011-10-10 13:09 ` Theodore Tso
2011-10-13 0:28 ` Dave Chinner
2011-10-14 15:47 ` Ted Ts'o
2011-10-11 13:14 ` Serge E. Hallyn
2011-10-11 15:49 ` Andrew G. Morgan
2011-10-12 2:31 ` Serge E. Hallyn
2011-10-12 20:51 ` Lennart Poettering
2011-10-08 9:53 ` A Plumber’s " Bastien ROUCARIES
2011-10-09 3:15 ` Alex Elsayed
2011-10-07 16:07 ` Valdis.Kletnieks
2011-10-07 12:35 ` Vivek Goyal
2011-10-07 18:59 ` Greg KH
2011-10-09 12:20 ` Kay Sievers
2011-10-09 8:45 ` Rusty Russell
2011-10-11 23:16 ` Andrew Morton
2011-10-12 0:53 ` Frederic Weisbecker
2011-10-12 0:59 ` Frederic Weisbecker
[not found] ` <20111012174014.GE6281@google.com>
2011-10-12 18:16 ` Cyrill Gorcunov
2011-10-14 15:38 ` Frederic Weisbecker
2011-10-14 16:01 ` Cyrill Gorcunov
2011-10-14 16:08 ` Cyrill Gorcunov
2011-10-14 16:19 ` Frederic Weisbecker
2011-10-19 21:19 ` Paul Menage
2011-10-19 21:12 ` Paul Menage
2011-10-19 23:03 ` Lennart Poettering
2011-10-19 23:09 ` Paul Menage
2011-10-19 23:31 ` Lennart Poettering
2011-10-22 10:21 ` Frederic Weisbecker
2011-10-22 15:28 ` Lennart Poettering
2011-10-25 5:40 ` Li Zefan
2011-10-30 17:18 ` Lennart Poettering
2011-11-01 1:27 ` Li Zefan
[not found] <CAE2SPAZci=u__d58phePCftVr_e+i+N2YU-JYjGDG_b3TmYTSQ@mail.gmail.com>
2011-10-07 13:40 ` Alan Cox
2011-10-07 14:57 ` Alexander E. Patrakov
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