[RFC PATCH v1 1/7] fs: Add inode_get_ino() and implement get_ino() for NFS

[Mickaël Salaün]

On Fri, Oct 11, 2024 at 05:30:12AM -0700, Christoph Hellwig wrote:
> On Thu, Oct 10, 2024 at 05:26:41PM +0200, Mickaël Salaün wrote:
> > When a filesystem manages its own inode numbers, like NFS's fileid shown
> > to user space with getattr(), other part of the kernel may still expose
> > the private inode->ino through kernel logs and audit.
> > 
> > Another issue is on 32-bit architectures, on which ino_t is 32 bits,
> > whereas the user space's view of an inode number can still be 64 bits.
> > 
> > Add a new inode_get_ino() helper calling the new struct
> > inode_operations' get_ino() when set, to get the user space's view of an
> > inode number.  inode_get_ino() is called by generic_fillattr().
> > 
> > Implement get_ino() for NFS.
> 
> The proper interface for that is ->getattr, and you should use that for
> all file systems (through the proper vfs wrappers).

How to get the inode number with ->getattr and only a struct inode?

> 
> And yes, it's really time to move to a 64-bit i_ino, but that's a
> separate discussion.