Re: [stable] Stable patches for ext4

[Greg KH <greg@kroah.com>]

On Sat, Oct 18, 2008 at 03:28:56PM -0400, Theodore Tso wrote:
> On Sat, Oct 18, 2008 at 10:03:05AM -0700, Greg KH wrote:
> > 
> > Heh, you do realize that hundreds of thousands of users are going to be
> > using 2.6.27.x "for production" as at least 3 distros are being based
> > off of it?
> > 
> > So, either you send these patches to us if you want to have a sane idea
> > of what the distros are using, or you rely on the distros themselves to
> > get it right in cherry-picking from upstream here.  I know one distro
> > already has done this, and I'm sure others have as well.
> > 
> > It comes down to who you trust, a random distro engineer, or you and
> > your group of engineers :)
> 
> Heh**2.  What Fedora 10 at least is going to be doing is grabbing the
> equivalent of ext4-stable.  If it were completely up to me, and Eric
> Sandeen from Red Hat has made the same wish (although I suspectly
> somewhat in jest) on #ext4, it would be great if we could pour all of
> ext4-stable (i.e., what we got added into the malinline during the
> 2.6.28 merge window) into 2.6.27.x.  That would be easier for me to
> support as well.  Only problem is that it rather blatently violates
> the criteria as set forth in Documentation/stable_kernel_rules.txt.
> (i.e., there are factor-of-five performance enhacements, code
> cleanups, ext4dev gets renamed to ext4, etc.)
> 
> Regardless what goes into 2.6.27.x, I'll probably have to maintain a
> patchset of everything else "left over" for those distributions that
> want to be aggressive about letting users starting to play with ext4.  

Fair enough, want to send us the patches you know you want us to take
for 2.6.27 right now?

> > If you feel the second tree is something that you can support, and you
> > feel is necessary for users if they want to use ext4 on this kernel
> > release, I'd be glad to review them for inclusion.
> 
> If distribution users are going to use ext4 for real, then ENOSPC
> issues are a real problem, and they should be solved.  But there are a
> large number of patches involved here, and many of them go over 100
> lines (although granted the wc -l listed below includes the commit
> comments):
> 
>   161 /tmp/p/0015-ext4-invalidate-pages-if-delalloc-block-allocation.patch
>   211 /tmp/p/0016-ext4-Make-sure-all-the-block-allocation-paths-reser.patch
>   123 /tmp/p/0017-ext4-Retry-block-reservation.patch
>   307 /tmp/p/0018-ext4-Add-percpu-dirty-block-accounting.patch
>   113 /tmp/p/0019-ext4-Switch-to-non-delalloc-mode-when-we-are-low-on.patch
>    93 /tmp/p/0020-ext4-Signed-arithmetic-fix.patch
>    64 /tmp/p/0021-ext4-Fix-ext4-nomballoc-allocator-for-ENOSPC.patch
>    86 /tmp/p/0022-ext4-Don-t-add-the-inode-to-journal-handle-until-af.patch
>   190 /tmp/p/0023-ext4-Retry-block-allocation-if-we-have-free-blocks.patch
>    50 /tmp/p/0024-ext4-truncate-block-allocated-on-a-failed-ext4_writ.patch
>   169 /tmp/p/0025-ext4-Properly-update-i_disksize.patch
> 
> I am very confident about these patches, since they hit the ext4 tree
> sometime in 2.6.27-rc2 or -rc3, so they've gotten quite a bit of
> testing.  I just put them at the end of the for-stable-enospc branch
> because they do technically violate the -stable rules.
> 
> So it's ultimately to you and Chris.  I'm happy to support any one of
> for-stable, for-stable-enospc, or ext4-stable in 2.6.27.x.  The last
> is less work for me since I won't have to create "this-is-in-mainline-
> please-consider-this-for-your-distro" patch sets.  The real question
> is what you're willing to review, and whether other -stable reviewers
> will end up complaining and sending NACK's because they violate the
> -stable rules.  (To be fair, if some other subsystem did this and I
> saw such patches, with my stable reviewer hat on I'd at least send up
> a red flag.)

I'm still undecided about this.  For now, I'm thinking we should hold
off, but as 2.6.27 gets a bit more "stable", I might be willing to
reconsider just because of what it is being used as (for a base for a
wide range of distros/users.)

Sound fair?

thanks,

greg k-h