Re: [Cluster-devel] [PATCH] gfs2: add error handling for kmem_cache_zalloc

[Steven Whitehouse]

Hi,


On 12/06/18 08:24, cgxu519@xxxxxxx wrote:
> > 在 2018年6月12日，上午11:38，Zhouyang Jia <jiazhouyang09@xxxxxxxxx> 写道：
> >
> > When kmem_cache_zalloc fails, the lack of error-handling code may
> > cause unexpected results.
> >
> > This patch adds error-handling code after calling kmem_cache_zalloc.
> Should not fail on this case.
>
> Thanks,
> Chengguang.
Indeed. It is one of the few GFP_NOFAIL allocations left in GFS2. It 
would be good to figure out how to remove the last few of these 
allocations, but simply adding a check for a NULL return is not the 
right solution here anyway. I would also add that if this problem was 
easier then I'm sure we'd have solved it before - the right answer is 
not very obvious in this case,

Steve.

> > Signed-off-by: Zhouyang Jia <jiazhouyang09@xxxxxxxxx>
> > ---
> > fs/gfs2/trans.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/fs/gfs2/trans.c b/fs/gfs2/trans.c
> > index 064c9a0..da81eb4 100644
> > --- a/fs/gfs2/trans.c
> > +++ b/fs/gfs2/trans.c
> > @@ -130,6 +130,9 @@ static struct gfs2_bufdata *gfs2_alloc_bufdata(struct gfs2_glock *gl,
> > 	struct gfs2_bufdata *bd;
> >
> > 	bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
> > +	if (!bd)
> > +		return NULL;
> > +
> > 	bd->bd_bh = bh;
> > 	bd->bd_gl = gl;
> > 	bd->bd_ops = lops;
> > --
> > 2.7.4