fs: port ->getattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

2 files changed, 3 insertions, 3 deletions

diff --git a/fs/coda/coda_linux.h b/fs/coda/coda_linux.h
index b762525eb5a2..cc69a0f15b41 100644
--- a/fs/coda/coda_linux.h
+++ b/fs/coda/coda_linux.h
@@ -49,7 +49,7 @@ int coda_release(struct inode *i, struct file *f);
 int coda_permission(struct user_namespace *mnt_userns, struct inode *inode,
 		    int mask);
 int coda_revalidate_inode(struct inode *);
-int coda_getattr(struct user_namespace *, const struct path *, struct kstat *,
+int coda_getattr(struct mnt_idmap *, const struct path *, struct kstat *,
 		 u32, unsigned int);
 int coda_setattr(struct mnt_idmap *, struct dentry *, struct iattr *);
 
diff --git a/fs/coda/inode.c b/fs/coda/inode.c
index 8e5a431f7eb5..d661e6cf17ac 100644
--- a/fs/coda/inode.c
+++ b/fs/coda/inode.c
@@ -251,12 +251,12 @@ static void coda_evict_inode(struct inode *inode)
 	coda_cache_clear_inode(inode);
 }
 
-int coda_getattr(struct user_namespace *mnt_userns, const struct path *path,
+int coda_getattr(struct mnt_idmap *idmap, const struct path *path,
 		 struct kstat *stat, u32 request_mask, unsigned int flags)
 {
 	int err = coda_revalidate_inode(d_inode(path->dentry));
 	if (!err)
-		generic_fillattr(&init_user_ns, d_inode(path->dentry), stat);
+		generic_fillattr(&nop_mnt_idmap, d_inode(path->dentry), stat);
 	return err;
 }