On Fri, Sep 06, 2024 at 04:34:52PM GMT, Alexander Mikhalitsyn wrote: > Link: https://lore.kernel.org/linux-fsdevel/20240904-baugrube-erhoben-b3c1c49a2645@brauner/ > Suggested-by: Christian Brauner <brauner@xxxxxxxxxx> > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx> > --- > fs/mnt_idmapping.c | 22 ++++++++++++++++++++-- > include/linux/mnt_idmapping.h | 1 + > 2 files changed, 21 insertions(+), 2 deletions(-) > > diff --git a/fs/mnt_idmapping.c b/fs/mnt_idmapping.c > index 3c60f1eaca61..cbca6500848e 100644 > --- a/fs/mnt_idmapping.c > +++ b/fs/mnt_idmapping.c > @@ -32,6 +32,15 @@ struct mnt_idmap nop_mnt_idmap = { > }; > EXPORT_SYMBOL_GPL(nop_mnt_idmap); > > +/* > + * Carries the invalid idmapping of a full 0-4294967295 {g,u}id range. > + * This means that all {g,u}ids are mapped to INVALID_VFS{G,U}ID. > + */ > +struct mnt_idmap invalid_mnt_idmap = { > + .count = REFCOUNT_INIT(1), > +}; > +EXPORT_SYMBOL_GPL(invalid_mnt_idmap); > + > /** > * initial_idmapping - check whether this is the initial mapping > * @ns: idmapping to check > @@ -75,6 +84,8 @@ vfsuid_t make_vfsuid(struct mnt_idmap *idmap, > > if (idmap == &nop_mnt_idmap) > return VFSUIDT_INIT(kuid); > + if (idmap == &invalid_mnt_idmap) > + return INVALID_VFSUID; Could possibly deserve an: if (unlikely(idmap == &invalid_mnt_idmap)) return INVALID_VFSUID; and technically I guess we could also do: if (likely(idmap == &nop_mnt_idmap)) return VFSUIDT_INIT(kuid); but not that relevant for this patch.
