[PATCH] erofs-utils: avoid unnecessary insert behavior when not deduplicating

[Yue Hu]

Hi Xiang,

On Fri, 14 Oct 2022 10:15:27 +0800
Gao Xiang <hsiangkao at linux.alibaba.com> wrote:

> On Fri, Oct 14, 2022 at 09:48:46AM +0800, Yue Hu wrote:
> > On Thu, 13 Oct 2022 16:59:26 +0800
> > Gao Xiang <hsiangkao at linux.alibaba.com> wrote:
> >   
> > > Hi Yue,
> > > 
> > > On Thu, Oct 13, 2022 at 12:00:11PM +0800, Yue Hu wrote:  
> > > > From: Yue Hu <huyue2 at coolpad.com>
> > > > 
> > > > We should do nothing in dedupe inserting when it's not configured.
> > > > 
> > > > Signed-off-by: Yue Hu <huyue2 at coolpad.com>
> > > > ---    
> > > 
> > > Thanks for the patch, do you observe some strange happening?   
> > 
> > I can see malloc/memcpy at runtime when dedupe is disabled. So, just skip.  
> 
> Would you mind confirming the numbers of e->length and window_size 
> at that time?

The caller to insert function is just checking "!may_inline && !may_packing".

Check below (-zlz4hc foo.img foo/):

Processing .gitignore ...
<E> erofs: z_erofs_dedupe_insert() Line[105] e->length 84, window_size 0
Processing Kconfig.freezer ...
<E> erofs: z_erofs_dedupe_insert() Line[105] e->length 92, window_size 0
Processing Kconfig.hz ...
<E> erofs: z_erofs_dedupe_insert() Line[105] e->length 1709, window_size 0

--- a/lib/dedupe.c
+++ b/lib/dedupe.c
@@ -102,6 +102,8 @@ int z_erofs_dedupe_insert(struct z_erofs_inmem_extent *e,
        if (e->length < window_size)
                return 0;

+       erofs_err("e->length %u, window_size %u", e->length, window_size);
+
        di = malloc(sizeof(*di) + e->length - window_size);

Thanks.

> 
> Thanks,
> Gao Xiang
> 
> >   
> > > 
> > > IMO, If dedupe is not enabled, window_size will be 0 I think.
> > > However, I think we might need to disable it explicitly like below.
> > > 
> > > So,
> > > Reviewed-by: Gao Xiang <hsiangkao at linux.alibaba.com>
> > > 
> > > Thanks,
> > > Gao Xiang