Re: [PATCH] xfs: Add check for unsupported xflags

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Mon, Aug 31, 2020 at 09:37:45PM +0800, Xiao Yang wrote:
> Current ioctl(FSSETXATTR) ignores unsupported xflags silently
> so it it not clear for user to know unsupported xflags.
> For example, use ioctl(FSSETXATTR) to set dax flag on kernel
> v4.4 which doesn't support dax flag:
> --------------------------------
> # xfs_io -f -c "chattr +x" testfile;echo $?
> 0
> # xfs_io -c "lsattr" testfile
> ----------------X testfile
> --------------------------------
> 
> Add check to report unsupported info as ioctl(SETXFLAGS) does.
> 
> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
> ---
>  fs/xfs/xfs_ioctl.c      | 4 ++++
>  include/uapi/linux/fs.h | 8 ++++++++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 6f22a66777cd..cfe7f20c94fe 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1439,6 +1439,10 @@ xfs_ioctl_setattr(
>  
>  	trace_xfs_ioctl_setattr(ip);
>  
> +	/* Check if fsx_xflags have unsupported xflags */
> +	if (fa->fsx_xflags & ~FS_XFLAG_ALL)
> +                return -EOPNOTSUPP;

Shouldn't this be in vfs_ioc_fssetxattr_check, since we're checking
against all the vfs defined XFLAGS?

--D

> +
>  	code = xfs_ioctl_setattr_check_projid(ip, fa);
>  	if (code)
>  		return code;
> diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
> index f44eb0a04afd..31b6856f6877 100644
> --- a/include/uapi/linux/fs.h
> +++ b/include/uapi/linux/fs.h
> @@ -142,6 +142,14 @@ struct fsxattr {
>  #define FS_XFLAG_COWEXTSIZE	0x00010000	/* CoW extent size allocator hint */
>  #define FS_XFLAG_HASATTR	0x80000000	/* no DIFLAG for this	*/
>  
> +#define FS_XFLAG_ALL \
> +	(FS_XFLAG_REALTIME | FS_XFLAG_PREALLOC | FS_XFLAG_IMMUTABLE | \
> +	 FS_XFLAG_APPEND | FS_XFLAG_SYNC | FS_XFLAG_NOATIME | FS_XFLAG_NODUMP | \
> +	 FS_XFLAG_RTINHERIT | FS_XFLAG_PROJINHERIT | FS_XFLAG_NOSYMLINKS | \
> +	 FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT | FS_XFLAG_NODEFRAG | \
> +	 FS_XFLAG_FILESTREAM | FS_XFLAG_DAX | FS_XFLAG_COWEXTSIZE | \
> +	 FS_XFLAG_HASATTR)
> +
>  /* the read-only stuff doesn't really belong here, but any other place is
>     probably as bad and I don't want to create yet another include file. */
>  
> -- 
> 2.25.1
> 
> 
>