On Tue, Jan 12, 2021 at 11:01:00PM +0100, Christian Brauner wrote:

The generic_fillattr() helper fills in the basic attributes associated
with an inode. Enable it to handle idmapped mounts. If the inode is
accessed through an idmapped mount we need to map it according to the
mount's user namespace before we store the uid and gid.
If the initial user namespace is passed nothing changes so non-idmapped
mounts will see identical behavior as before.

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>