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

From: Steven Whitehouse
Date: Tue Jun 12 2018 - 08:18:53 EST


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.

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,


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;