Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively

From	Linus Torvalds <torvalds@linux-foundation.org>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively
Date	2017-10-02 01:20 +0200
Message-ID	<uvVGG-8gb-3@gated-at.bofh.it> (permalink)
References	(6 earlier) <uvBoB-3Mo-1@gated-at.bofh.it> <uvLei-1Zz-17@gated-at.bofh.it> <uvLei-1Zz-15@gated-at.bofh.it> <uvRtn-5BE-1@gated-at.bofh.it> <uvV3Y-7M7-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Sun, Oct 1, 2017 at 3:34 PM, Dave Chinner <david@fromorbit.com> wrote:
>
> We already have a change counter on the inode, which is modified on
> any data or metadata write (i_version) under filesystem locks.  The
> i_version counter has well defined semantics - it's required by
> NFSv4 to increment on any metadata or data change - so we should be
> able to rely on it's behaviour to implement IMA as well.

I actually think i_version has exactly the wrong semantics.

Afaik, it doesn't actually version the file _data_ at all, it only
versions "inode itself changed".

But I might have missed something obvious. The updates are hidden in
some odd places sometimes.

              Linus

Thread

[RFC PATCH 0/3] define new read_iter file operation rwf flag Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-28 14:50 +0200
  [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-28 14:50 +0200
    Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Dave Chinner <david@fromorbit.com> - 2017-09-29 00:10 +0200
      Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-29 01:40 +0200
        Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-29 02:20 +0200
          Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-29 02:40 +0200
            Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-29 04:00 +0200
              Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-29 05:30 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively ebiederm@xmission.com (Eric W. Biederman) - 2017-10-01 03:40 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-10-01 14:10 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-10-01 20:50 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Dave Chinner <david@fromorbit.com> - 2017-10-02 00:40 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-10-02 01:20 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Dave Chinner <david@fromorbit.com> - 2017-10-02 06:00 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-10-02 01:50 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively ebiederm@xmission.com (Eric W. Biederman) - 2017-10-02 05:30 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-10-02 14:30 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Dave Chinner <david@fromorbit.com> - 2017-10-02 06:40 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-10-02 14:20 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Jeff Layton <jlayton@redhat.com> - 2017-10-02 14:50 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively ebiederm@xmission.com (Eric W. Biederman) - 2017-10-02 00:10 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Linus Torvalds <torvalds@linux-foundation.org> - 2017-10-02 00:30 +0200
                Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been  taken exclusively Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-10-02 02:00 +0200
  [RFC PATCH 1/3] fs: define new read_iter rwf flag Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-28 14:50 +0200
    Re: [RFC PATCH 1/3] fs: define new read_iter rwf flag Matthew Wilcox <willy@infradead.org> - 2017-09-28 16:00 +0200
      Re: [RFC PATCH 1/3] fs: define new read_iter rwf flag Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-09-28 16:40 +0200
      Re: [RFC PATCH 1/3] fs: define new read_iter rwf flag Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-28 18:00 +0200

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