Re: [PATCH v2] btrfs-progs: filesystem: du: skip file that permission denied

[Sidong Yang <realwakka@gmail.com>]

On Mon, Nov 22, 2021 at 09:20:00AM +0200, Nikolay Borisov wrote:
> 
> 
> On 21.11.21 г. 17:15, Sidong Yang wrote:
> > This patch handles issue #421. Filesystem du command fails and exit
> > when it access file that has permission denied. But it can continue the
> > command except the files. This patch recovers ret value when permission
> > denied.
> > 
> > Signed-off-by: Sidong Yang <realwakka@gmail.com>
> 
> 
> The code itself is fine so :
> 
> 
> Reviewed-by: Nikolay Borisov <nborisov@suse.com>
> 
> 
> OTOH when I looked at the code rather than just the patch I can't help
> but wonder shouldn't we actually structure this the way you initially
> proposed but also add a debug output along the lines of "skipping
> file/dir XXXX due to permission denied", otherwise users might not be
> able to account for some space and they can possibly wonder that
> something is wrong with btrfs fi du command.

You mean that it would be better that print some debug message than
skipping silently. I agree. So I would add this code in condition.

fprintf(stderr, "skipping file/dir: %s : %m\n", entry->d_name);

I think it's okay that it prints when ENOTTY occurs. Is this code what
you meant?
> 
> 
> > ---
> >  cmds/filesystem-du.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/cmds/filesystem-du.c b/cmds/filesystem-du.c
> > index 5865335d..fb7753ca 100644
> > --- a/cmds/filesystem-du.c
> > +++ b/cmds/filesystem-du.c
> > @@ -403,7 +403,7 @@ static int du_walk_dir(struct du_dir_ctxt *ctxt, struct rb_root *shared_extents)
> >  						  dirfd(dirstream),
> >  						  shared_extents, &tot, &shr,
> >  						  0);
> > -				if (ret == -ENOTTY) {
> > +				if (ret == -ENOTTY || ret == -EACCES) {
> >  					ret = 0;
> >  					continue;
> >  				} else if (ret) {
> >