fs: port ->setattr() 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, 4 insertions, 4 deletions

diff --git a/fs/hpfs/hpfs_fn.h b/fs/hpfs/hpfs_fn.h
index 167ec6884642..f5a2476c47bf 100644
--- a/fs/hpfs/hpfs_fn.h
+++ b/fs/hpfs/hpfs_fn.h
@@ -280,7 +280,7 @@ void hpfs_init_inode(struct inode *);
 void hpfs_read_inode(struct inode *);
 void hpfs_write_inode(struct inode *);
 void hpfs_write_inode_nolock(struct inode *);
-int hpfs_setattr(struct user_namespace *, struct dentry *, struct iattr *);
+int hpfs_setattr(struct mnt_idmap *, struct dentry *, struct iattr *);
 void hpfs_write_if_changed(struct inode *);
 void hpfs_evict_inode(struct inode *);
 
diff --git a/fs/hpfs/inode.c b/fs/hpfs/inode.c
index 82208cc28ebd..e50e92a42432 100644
--- a/fs/hpfs/inode.c
+++ b/fs/hpfs/inode.c
@@ -257,7 +257,7 @@ void hpfs_write_inode_nolock(struct inode *i)
 	brelse(bh);
 }
 
-int hpfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+int hpfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
@@ -275,7 +275,7 @@ int hpfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 	if ((attr->ia_valid & ATTR_SIZE) && attr->ia_size > inode->i_size)
 		goto out_unlock;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		goto out_unlock;
 
@@ -289,7 +289,7 @@ int hpfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 		hpfs_truncate(inode);
 	}
 
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 
 	hpfs_write_inode(inode);