Re: regression in 2.6.37?

[Jiro SEKIBA <jir-hfpbi5WX9J54Eiagz67IpQ@public.gmane.org>]

At Mon, 28 Feb 2011 13:52:56 +0900 (JST),
Ryusuke Konishi wrote:
> 
> On Mon, 28 Feb 2011 11:21:46 +0900 (JST), Ryusuke Konishi wrote:
> > On Mon, 28 Feb 2011 10:58:36 +0900, Jiro SEKIBA wrote:
> > > 
> > > At Mon, 28 Feb 2011 10:33:24 +0900,
> > > Jiro SEKIBA wrote:
> > > > 
> > > > Hi,
> > > > 
> > > > I found that none of the checpoints are flagged 'i'.
> > > > It looks like it happens after 2.6.37.
> > > > 
> > > > So whenever I only execute "chcp ss <cp>" without any filesystem change,
> > > > nilfs volume create new cp without 'i'.
> > > > Before 2.6.37, it creates new cp with 'i'.
> > > 
> > > This, by the way, causes that nilfs2_ss_manager creates
> > > snapshots forever and useless as a result.
> > > 
> > > So I would really like to turn it back to the normal behavior.
> > > It is really critical for the application.
> > > 
> > > thanks
> > > 
> > > regards,
> > 
> > Arrh, that sounds so bad.  Ok, I'll look into the problem ASAP.
> > 
> > Ryusuke Konishi
> 
> Actually, this tourned out to be a regression on 2.6.37.
> The following patch will fix this.
> 
> Could you confirm that it corrects your problem?

Thank you for the prompt reaction!
I confirmed the patch worked fine with 2.6.38-rc6.

thanks again

regards,

> Thanks,
> Ryusuke Konishi
> ---
> From: Ryusuke Konishi <konishi.ryusuke-Zyj7fXuS5i5L9jVzuh4AOg@public.gmane.org>
> 
> nilfs2: fix regression that i-flag is not set on changeless checkpoints
> 
> According to the report from Jiro SEKIBA titled "regression in
> 2.6.37?"  (Message-Id: <8739n8vs1f.wl%jir-27yqGEOhnJbQT0dZR+AlfA@public.gmane.org>), on 2.6.37 and
> later kernels, lscp command no longer displays "i" flag on checkpoints
> that snapshot operations or garbage collection created.
> 
> This is a regression of nilfs2 checkpointing function, and it's
> critical since it broke behavior of a part of nilfs2 applications.
> For instance, snapshot manager of TimeBrowse gets to create
> meaningless snapshots continuously; snapshot creation triggers another
> checkpoint, but applications cannot distinguish whether the new
> checkpoint contains meaningful changes or not without the i-flag.
> 
> This patch fixes the regression and brings that application behavior
> back to normal.
> 
> Reported-by: Jiro SEKIBA <jir-hfpbi5WX9J54Eiagz67IpQ@public.gmane.org>
> Signed-off-by: Ryusuke Konishi <konishi.ryusuke-Zyj7fXuS5i5L9jVzuh4AOg@public.gmane.org>
> Cc: stable <stable-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>  [2.6.37]
> ---
>  fs/nilfs2/segment.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
> index 55ebae5..2de9f63 100644
> --- a/fs/nilfs2/segment.c
> +++ b/fs/nilfs2/segment.c
> @@ -430,7 +430,8 @@ static void nilfs_segctor_begin_finfo(struct nilfs_sc_info *sci,
>  	nilfs_segctor_map_segsum_entry(
>  		sci, &sci->sc_binfo_ptr, sizeof(struct nilfs_finfo));
>  
> -	if (inode->i_sb && !test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
> +	if (NILFS_I(inode)->i_root &&
> +	    !test_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags))
>  		set_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
>  	/* skip finfo */
>  }
> -- 
> 1.7.3.5
> 
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> 
> 


-- 
Jiro SEKIBA <jir-hfpbi5WX9J54Eiagz67IpQ@public.gmane.org>
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