vboxsf: Avoid an spurious warning if load_nls_xxx() fails

If an load_nls_xxx() function fails a few lines above, the 'sbi->bdi_id' is
still 0.
So, in the error handling path, we will call ida_simple_remove(..., 0)
which is not allocated yet.

In order to prevent a spurious "ida_free called for id=0 which is not
allocated." message, tweak the error handling path and add a new label.

Fixes: 0fd1695 ("fs: Add VirtualBox guest shared folder (vboxsf) support")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/d09eaaa4e2e08206c58a1a27ca9b3e81dc168773.1698835730.git.christophe.jaillet@wanadoo.fr
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Author: tititiou36

fs/vboxsf/super.c

@@ -151,7 +151,7 @@ static int vboxsf_fill_super(struct super_block *sb, struct fs_context *fc)
 		if (!sbi->nls) {
 			vbg_err("vboxsf: Count not load '%s' nls\n", nls_name);
 			err = -EINVAL;
-			goto fail_free;
+			goto fail_destroy_idr;
 		}
 	}
 
@@ -224,6 +224,7 @@ static int vboxsf_fill_super(struct super_block *sb, struct fs_context *fc)
 		ida_simple_remove(&vboxsf_bdi_ida, sbi->bdi_id);
 	if (sbi->nls)
 		unload_nls(sbi->nls);
+fail_destroy_idr:
 	idr_destroy(&sbi->ino_idr);
 	kfree(sbi);
 	return err;