Re: [PATCH] ovl: Support FS_IOC_[SG]ETFLAGS and FS_IOC_FS[SG]ETXATTR ioctls on directories

[Amir Goldstein <amir73il@gmail.com>]

On Tue, Sep 22, 2020 at 11:15 AM Xiao Yang <yangx.jy@cn.fujitsu.com> wrote:
>
> On 2020/9/21 17:09, Amir Goldstein wrote:
> > On Mon, Sep 21, 2020 at 11:55 AM Xiao Yang<yangx.jy@cn.fujitsu.com>  wrote:
> >> On 2020/9/21 16:17, Amir Goldstein wrote:
> >>> On Mon, Sep 21, 2020 at 10:41 AM Xiao Yang<yangx.jy@cn.fujitsu.com>   wrote:
> >>>> Factor out ovl_ioctl() and ovl_compat_ioctl() and take use of them for
> >>>> directories.
> >>>>
> >>>> Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
> >>>> ---
> >>> This change is buggy. I had already posted it and self NACKed myself [1].
> >>>
> >>> You can find an hopefully non-buggy version of it on my ovl-shutdown [2] branch.
> >>>
> >>> As long as you are changing ovl_ioctl(), please also take the second
> >>> commit on that
> >>> branch to replace the open coded capability check with the
> >>> vfs_ioc_setflags_prepare()
> >>> generic helper.
> >> Hi Amir,
> >>
> >> Thanks a lot for your quick reply. :-)
> >> I will try to read and understand the metioned patches on your
> >> ovl-shutdown branch.
> > Please also verify my claim in the patch commit message, that the
> > the test result of xfstest generic/079 changes from "notrun" to "success".
> Hi Amir,
>
> With your patches, I have confirmed that generic/079 actually changed from
> "notrun" to "success".  Besides, one minor issue:
> Could we avoid the following compiler warning?
> -------------------------------------------------
> fs/overlayfs/readdir.c: In function ‘ovl_dir_real_file’:
> fs/overlayfs/readdir.c:883:37: warning: passing argument 1 of
> ‘ovl_dir_open_realfile’ discards ‘const’ qualifier from pointer target
> type [-Wdiscarded-qualifiers]
>    883 |    realfile = ovl_dir_open_realfile(file, &upperpath);
>        |                                     ^~~~
> fs/overlayfs/readdir.c:842:56: note: expected ‘struct file *’ but
> argument is of type ‘const struct file *’
>    842 | static struct file *ovl_dir_open_realfile(struct file *file,
>        |                                           ~~~~~~~~~~~~~^~~~
> -------------------------------------------------
>

Shouldn't be a problem to change ovl_dir_open_realfile()
to take a const struct file * argument I think.

Thanks,
Amir.