Re: [PATCH] erofs: code cleanup by removing ifdef macro surrounding

[Gao Xiang <hsiangkao@redhat.com>]

On Tue, May 26, 2020 at 06:29:00PM +0800, cgxu wrote:
> On 5/26/20 5:49 PM, Gao Xiang wrote:
> > Hi Chengguang,
> > 
> > On Tue, May 26, 2020 at 05:03:43PM +0800, Chengguang Xu wrote:
> > > Define erofs_listxattr and erofs_xattr_handlers to NULL when
> > > CONFIG_EROFS_FS_XATTR is not enabled, then we can remove many
> > > ugly ifdef macros in the code.
> > > 
> > > Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
> > > ---
> > > Only compile tested.
> > > 
> > >   fs/erofs/inode.c | 6 ------
> > >   fs/erofs/namei.c | 2 --
> > >   fs/erofs/super.c | 4 +---
> > >   fs/erofs/xattr.h | 7 ++-----
> > >   4 files changed, 3 insertions(+), 16 deletions(-)
> > > 
> > > diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> > > index 3350ab65d892..7dd4bbe9674f 100644
> > > --- a/fs/erofs/inode.c
> > > +++ b/fs/erofs/inode.c
> > > @@ -311,27 +311,21 @@ int erofs_getattr(const struct path *path, struct kstat *stat,
> > >   const struct inode_operations erofs_generic_iops = {
> > >   	.getattr = erofs_getattr,
> > > -#ifdef CONFIG_EROFS_FS_XATTR
> > >   	.listxattr = erofs_listxattr,
> > > -#endif
> > 
> > It seems equivalent. And it seems ext2 and f2fs behave in the same way...
> 
> I posted similar patch for ext2 and Jack merged to
> his tree the other day, though that series also
> included a real bugfix. I also posted similar patch
> to f2fs, so if erofs and f2fs merge these patches
> then all three will behave in the same way, ;-)
> 
> You may refer below link for the detail.
> 
> https://lore.kernel.org/linux-ext4/20200522044035.24190-2-cgxu519@mykernel.net/

Thanks for your link...

> 
> 
> > But I'm not sure whether we'd return 0 (if I didn't see fs/xattr.c by mistake)
> > or -EOPNOTSUPP here... Some thoughts about this? >
> > Anyway, I'm fine with that if return 0 is okay here, but I'd like to know your
> > and Chao's thoughts about this... I will play with it later as well.
> 
> Originally, we set erofs_listxattr to ->listxattr only
> when the config macro CONFIG_EROFS_FS_XATTR is enabled,
> it means that erofs_listxattr() never returns -EOPNOTSUPP
> in any case, so actually there is no logic change here,
> right?

Yeah, I agree there is no logic change, so I'm fine with the patch.
But I'm little worry about if return 0 is actually wrong here...

see the return value at:
http://man7.org/linux/man-pages/man2/listxattr.2.html

Thanks,
Gao Xiang

> 
> 
> Thanks,
> cgxu
>