Re: [RFC 2/3] xfs_io: Add ext4 support to show FS_IOC_FSGETXATTR details

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Dec 12, 2024 at 09:33:29AM +1100, Dave Chinner wrote:
> On Wed, Dec 11, 2024 at 10:17:06AM -0800, Darrick J. Wong wrote:
> > On Wed, Dec 11, 2024 at 01:24:03PM +0530, Ojaswin Mujoo wrote:
> > > Currently with stat we only show FS_IOC_FSGETXATTR details
> > > if the filesystem is XFS. With extsize support also coming
> > > to ext4 make sure to show these details when -c "stat" or "statx"
> > > is used.
> > > 
> > > No functional changes for filesystems other than ext4.
> > > 
> > > Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
> > > ---
> > >  io/stat.c | 38 +++++++++++++++++++++-----------------
> > >  1 file changed, 21 insertions(+), 17 deletions(-)
> > > 
> > > diff --git a/io/stat.c b/io/stat.c
> > > index 326f2822e276..d06c2186cde4 100644
> > > --- a/io/stat.c
> > > +++ b/io/stat.c
> > > @@ -97,14 +97,14 @@ print_file_info(void)
> > >  		file->flags & IO_TMPFILE ? _(",tmpfile") : "");
> > >  }
> > >  
> > > -static void
> > > -print_xfs_info(int verbose)
> > > +static void print_extended_info(int verbose)
> > >  {
> > > -	struct dioattr	dio;
> > > -	struct fsxattr	fsx, fsxa;
> > > +	struct dioattr dio;
> > > +	struct fsxattr fsx, fsxa;
> > > +	bool is_xfs_fd = platform_test_xfs_fd(file->fd);
> > >  
> > > -	if ((xfsctl(file->name, file->fd, FS_IOC_FSGETXATTR, &fsx)) < 0 ||
> > > -	    (xfsctl(file->name, file->fd, XFS_IOC_FSGETXATTRA, &fsxa)) < 0) {
> > > +	if ((ioctl(file->fd, FS_IOC_FSGETXATTR, &fsx)) < 0 ||
> > > +		(is_xfs_fd && (xfsctl(file->name, file->fd, XFS_IOC_FSGETXATTRA, &fsxa) < 0))) {
> > 
> > Urgh... perhaps we should call FS_IOC_FSGETXATTR and if it returns zero
> > print whatever is returned, no matter what filesystem we think is
> > feeding us information?
> 
> Yes, please. FS_IOC_FSGETXATTR has been generic functionality for
> some time, we should treat it the same way for all filesystems.
> 
> > e.g.
> > 
> > 	if (ioctl(file->fd, FS_IOC_FSGETXATTR, &fsx)) < 0) {
> > 		if (is_xfs_fd || (errno != EOPNOTSUPP &&
> > 				  errno != ENOTTY))
> > 			perror("FS_IOC_GETXATTR");
> 
> Why do we even need "is_xfs_fd" there? XFS will never give a
> EOPNOTSUPP or ENOTTY error to this or the FS_IOC_GETXATTRA ioctl...

Yeah, in hindsight I don't think it's needed for FS_IOC_FSGETXATTR, but
it's definitely nice for XFS_IOC_FSGETXATTRA (which is not implemented
outside xfs) so that you don't get unnecessary error messages on ext4.

--D

> -Dave.
> -- 
> Dave Chinner
> david@fromorbit.com
>