Re: [PATCH v1 44/59] 9p-local.c: remove unneeded label in local_unlinkat_common()

[Daniel Henrique Barboza]

On 1/7/20 10:53 AM, Greg Kurz wrote:
> On Mon,  6 Jan 2020 15:24:10 -0300
> Daniel Henrique Barboza <address@hidden> wrote:
>
> > 'err_out' can be replaced by 'return ret' in the error conditions
> > the jump was being made.
> >
> > CC: Greg Kurz <address@hidden>
> > Signed-off-by: Daniel Henrique Barboza <address@hidden>
> > ---
> >   hw/9pfs/9p-local.c | 12 +++++-------
> >   1 file changed, 5 insertions(+), 7 deletions(-)
> >
> > diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
> > index ca641390fb..f9bdd2ad7c 100644
> > --- a/hw/9pfs/9p-local.c
> > +++ b/hw/9pfs/9p-local.c
> > @@ -1094,12 +1094,12 @@ static int local_unlinkat_common(FsContext *ctx, int 
> > dirfd, const char *name,
> >   
> >               fd = openat_dir(dirfd, name);
> >               if (fd == -1) {
> > -                goto err_out;
> > +                return ret;
> >               }
> >               ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR);
> >               close_preserve_errno(fd);
> >               if (ret < 0 && errno != ENOENT) {
> > -                goto err_out;
> > +                return ret;
> >               }
> >           }
> >           map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
> > @@ -1107,16 +1107,14 @@ static int local_unlinkat_common(FsContext *ctx, int 
> > dirfd, const char *name,
> >               ret = unlinkat(map_dirfd, name, 0);
> >               close_preserve_errno(map_dirfd);
> >               if (ret < 0 && errno != ENOENT) {
> > -                goto err_out;
> > +                return ret;
> >               }
> >           } else if (errno != ENOENT) {
> > -            goto err_out;
> > +            return ret;
>
> Ouch... I now realize we can get there with ret == 0 when unlinking a
> directory in mapped-file mode. The function will wrongly return success
> despite the failure.... Since this function is supposed to return -1
> on error, I suggest to do that instead of return ret, and to drop the
> initialization of ret to -1, which wouldn't be needed anymore.
>
> Since this would fix a bug it makes sense to post it separately from
> this series. Rewrite the title/changelog accordingly and I'll merge
> it via the 9p tree.


Got it. I'll repost it separately with an updated title and commit msg.


Thanks,


Daniel

> >           }
> >       }
> >   
> > -    ret = unlinkat(dirfd, name, flags);
> > -err_out:
> > -    return ret;
> > +    return unlinkat(dirfd, name, flags);
> >   }
> >   
> >   static int local_remove(FsContext *ctx, const char *path)