Re: [git pull] vfs fixes

From	Linus Torvalds <torvalds@linux-foundation.org>
Newsgroups	linux.kernel
Subject	Re: [git pull] vfs fixes
Date	2017-04-03 03:00 +0200
Message-ID	<trYvD-83h-1@gated-at.bofh.it> (permalink)
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On Sun, Apr 2, 2017 at 5:43 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> Do you have any objections against the following (still untested) variant?
> I don't see any point in checking for flags & LOOKUP_RCU in case of !*s -
> flags is in register at that point, so...

Looks sane to me.

I had to go and double-check that "DCACHE_DIRECTORY_TYPE" is what
d_can_lookup() actually checks, so _that_ part is perhaps a bit
subtle, and might be worth noting in that comment that you edited.

So the real "rule" ends up being that we only ever look up things from
dentries of type DCACHE_DIRECTORY_TYPE set, and those had better have
DCACHE_RCUACCESS bit set.

And the only reason path_init() only checks it for that case is that
nd->root and nd->pwd both have to be of type d_can_lookup().

Do we check that when we set it? I hope/assume we do.

                      Linus

Thread

[git pull] vfs fixes Al Viro <viro@ZenIV.linux.org.uk> - 2017-04-02 19:10 +0200
  Re: [git pull] vfs fixes Linus Torvalds <torvalds@linux-foundation.org> - 2017-04-03 02:10 +0200
    Re: [git pull] vfs fixes Linus Torvalds <torvalds@linux-foundation.org> - 2017-04-03 02:20 +0200
      Re: [git pull] vfs fixes Al Viro <viro@ZenIV.linux.org.uk> - 2017-04-03 02:40 +0200
        Re: [git pull] vfs fixes Al Viro <viro@ZenIV.linux.org.uk> - 2017-04-03 02:50 +0200
          Re: [git pull] vfs fixes Linus Torvalds <torvalds@linux-foundation.org> - 2017-04-03 03:00 +0200
            Re: [git pull] vfs fixes Al Viro <viro@ZenIV.linux.org.uk> - 2017-04-03 04:30 +0200
              Re: [git pull] vfs fixes ebiederm@xmission.com (Eric W. Biederman) - 2017-04-03 08:10 +0200
                Re: [git pull] vfs fixes Al Viro <viro@ZenIV.linux.org.uk> - 2017-04-03 09:50 +0200
                Re: [git pull] vfs fixes Ian Kent <raven@themaw.net> - 2017-04-04 02:30 +0200
                Re: [git pull] vfs fixes Ian Kent <raven@themaw.net> - 2017-04-04 02:50 +0200
    Re: [git pull] vfs fixes Al Viro <viro@ZenIV.linux.org.uk> - 2017-04-03 02:30 +0200

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