Re: [PATCH 3.10 14/46] d_walk() might skip too much

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Sat, Jun 27, 2015 at 07:56:19AM +0200, Willy Tarreau wrote:
> On Fri, Jun 26, 2015 at 05:52:16PM -0700, Greg Kroah-Hartman wrote:
> > On Sat, Jun 20, 2015 at 10:41:14AM +0300, Jari Ruusu wrote:
> > > On 6/19/15, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> > > > I would much rather just include the "real" upstream patches, instead of
> > > > an odd backport.
> > > >
> > > > Jari, can you just backport the above referenced patches instead and
> > > > provide those backports?
> > > 
> > > I won't do that, sorry. It is more complicated than you think. It would
> > > involve backporting more VFS-re-write-patch-bombs than would be acceptable
> > > to stable kernel branch. Above mentioned d_walk() function that Al Viro
> > > modified in mainline don't even exist in 3.10.y and older brances.
> > > 
> > > My understanding is that complete backport of above mentioned "deal with
> > > deadlock in d_walk()" and "d_walk() might skip too much" patches to 3.10.y
> > > branch is to apply all these patches:
> > > 
> > > (a) backport of "deal with deadlock in d_walk()", by Ben Hutchings
> > > (b) dcache: Fix locking bugs in backported "deal with deadlock in d_walk()"
> > > (c) Al Viro's "d_walk() might skip too much" applied THREE times.
> > > 
> > > Of those, you merged (a) and (b) to 3.10.76 stable, and one copy of (c) to
> > > 3.10.80 stable.
> > > 
> > > The problem is that you didn't realize that "deal with deadlock in d_walk()"
> > > was applied to three different places in Ben Hutchings' backport, and that
> > > latest Al Viro's fix had to be also applied to three different places.
> > > Considering the sh*t that you have to deal with, nobody is blaming you for
> > > that mistake.
> > > 
> > > I am asking that you apply Al Viro's original "d_walk() might skip too much"
> > > patch TWO more times to 3.10.y stable branch. On both times, your patch tool
> > > will find the correct place of source file to modify, but with different
> > > offsets each time.
> > 
> > That's insane, and not how my tools work :(
> 
> No but I think it's just the patch command who found the proper location
> because the context was identical. That's what happens to me all the time
> with very old kernels, which is the reason why I must absolutely build
> them before the preview otherwise I'm sure to deliver something that
> doesn't even build :-)
> 
> > Can you provide the needed backport?  If it was in an earlier email in
> > this series, sorry, it's long gone from my mailbox, can you resend it?
> 
> Yes it was in the thread earlier this month. I'm appending it below. The
> following commits were referred to :
>   - ca5358e ("deal with deadlock in d_walk()")                                  
>   - 2159184 ("d_walk() might skip too much")                                    

Ok, that's a mess, thanks for clearing it up for me, I've now included
this in the 3.10-stable kernel.

greg k-h