Re: [PATCH] NFSD: Decrease nfsd_users in nfsd_startup_generic fail

["J. Bruce Fields" <bfields@fieldses.org>]

On Thu, Jul 31, 2014 at 08:56:13PM +0800, Kinglong Mee wrote:
> On 7/30/2014 22:16, J. Bruce Fields wrote:
> > Thanks!
> > 
> > On Wed, Jul 30, 2014 at 09:26:05PM +0800, Kinglong Mee wrote:
> >> If nfsd_startup_generic fail, nfsd_users isn't decreased right now.
> > 
> > Looks like that should only fail in out of memory cases?
> 
> Yes, it is.
> I found this problem through reviewing code.

Got it, thanks!  Applying for 3.17 and stable.

--b.

> 
> > 
> >> NFSD restarts will return 0 at the first nfsd_users checking,
> >> after that, nfs4_state_start_net() will meet a bad laundry_wq
> >> (I meet NULL), after nfsd4_grace timeout, the kernel will crash.
> > 
> > So this was introduced with 4539f14981ce02d48b212786a41c8bcfb62851b4
> > "nfsd: replace boolean nfsd_up flag by users counter".
> 
> Yes, I forget adding it.
> 
> thanks,
> Kinglong Mee
> 
> >> Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
> >> ---
> >>  fs/nfsd/nfssvc.c | 5 ++++-
> >>  1 file changed, 4 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
> >> index 5d026dc..752d56b 100644
> >> --- a/fs/nfsd/nfssvc.c
> >> +++ b/fs/nfsd/nfssvc.c
> >> @@ -221,7 +221,8 @@ static int nfsd_startup_generic(int nrservs)
> >>  	 */
> >>  	ret = nfsd_racache_init(2*nrservs);
> >>  	if (ret)
> >> -		return ret;
> >> +		goto dec_users;
> >> +
> >>  	ret = nfs4_state_start();
> >>  	if (ret)
> >>  		goto out_racache;
> >> @@ -229,6 +230,8 @@ static int nfsd_startup_generic(int nrservs)
> >>  
> >>  out_racache:
> >>  	nfsd_racache_shutdown();
> >> +dec_users:
> >> +	nfsd_users--;
> >>  	return ret;
> >>  }
> >>  
> >> -- 
> >> 1.9.3
> >>
> >