Re: [PATCH] btrfs: Fix backref.c selftest compilation warning

[Tang Bin]

Hi Qu:

On 2020/4/12 8:52, Qu Wenruo wrote:
> On 2020/4/11 äå11:49, Tang Bin wrote:
> > Fix missing braces compilation warning in the ARM
> > compiler environment:
> >      fs/btrfs/backref.c: In function âis_shared_data_backrefâ:
> >      fs/btrfs/backref.c:394:9: warning: missing braces around initializer [-Wmissing-braces]
> >        struct prelim_ref target = {0};
> >      fs/btrfs/backref.c:394:9: warning: (near initialization for âtarget.rbnodeâ) [-Wmissing-braces]
> GCC version please.
>
> It looks like you're using an older GCC, as it's pretty common certain
> prebuild tool chain is still using outdated GCC.
>
> In my environment with GCC 9.2.0 natively (on aarch64) it's completely fine.
> Thus personally I recommend to build your own tool chain using
> buildroot, or run it natively, other than rely on prebuilt one.

My environment:

 PC : Ubuntu 16.04

 Hardware : I.MX6ULL

 Tool Chain : arm-linux-gnueabihf-gcc (Linaro GCC 4.9-2017.01) 4.9.4

> In fact your fix could cause problem, as the original code is
> initializing all members to 0, but now it's uninitialized.
>
> You need to locate the root cause other than blindly follow the warning.

In hardware experiment, this approach is feasible.

Thanks.

Tang Bin

>