fs: port ->set_acl() 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>

3 files changed, 8 insertions, 6 deletions

diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index 33299e4f931ed..181d5677ccd1f 100644
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -707,7 +707,7 @@ int ntfs3_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	setattr_copy(idmap, inode, attr);
 
 	if (mode != inode->i_mode) {
-		err = ntfs_acl_chmod(mnt_idmap_owner(idmap), dentry);
+		err = ntfs_acl_chmod(idmap, dentry);
 		if (err)
 			goto out;
 
diff --git a/fs/ntfs3/ntfs_fs.h b/fs/ntfs3/ntfs_fs.h
index 41cd797b3c960..9d45a259695c6 100644
--- a/fs/ntfs3/ntfs_fs.h
+++ b/fs/ntfs3/ntfs_fs.h
@@ -859,7 +859,7 @@ unsigned long ntfs_names_hash(const u16 *name, size_t len, const u16 *upcase,
 /* globals from xattr.c */
 #ifdef CONFIG_NTFS3_FS_POSIX_ACL
 struct posix_acl *ntfs_get_acl(struct inode *inode, int type, bool rcu);
-int ntfs_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ntfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct posix_acl *acl, int type);
 int ntfs_init_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		  struct inode *dir);
@@ -868,7 +868,7 @@ int ntfs_init_acl(struct user_namespace *mnt_userns, struct inode *inode,
 #define ntfs_set_acl NULL
 #endif
 
-int ntfs_acl_chmod(struct user_namespace *mnt_userns, struct dentry *dentry);
+int ntfs_acl_chmod(struct mnt_idmap *idmap, struct dentry *dentry);
 int ntfs_permission(struct user_namespace *mnt_userns, struct inode *inode,
 		    int mask);
 ssize_t ntfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
diff --git a/fs/ntfs3/xattr.c b/fs/ntfs3/xattr.c
index 616df209feea7..370effca6b2c1 100644
--- a/fs/ntfs3/xattr.c
+++ b/fs/ntfs3/xattr.c
@@ -652,9 +652,11 @@ out:
 /*
  * ntfs_set_acl - inode_operations::set_acl
  */
-int ntfs_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry,
+int ntfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct posix_acl *acl, int type)
 {
+	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
+
 	return ntfs_set_acl_ex(mnt_userns, d_inode(dentry), acl, type, false);
 }
 
@@ -697,7 +699,7 @@ int ntfs_init_acl(struct user_namespace *mnt_userns, struct inode *inode,
 /*
  * ntfs_acl_chmod - Helper for ntfs3_setattr().
  */
-int ntfs_acl_chmod(struct user_namespace *mnt_userns, struct dentry *dentry)
+int ntfs_acl_chmod(struct mnt_idmap *idmap, struct dentry *dentry)
 {
 	struct inode *inode = d_inode(dentry);
 	struct super_block *sb = inode->i_sb;
@@ -708,7 +710,7 @@ int ntfs_acl_chmod(struct user_namespace *mnt_userns, struct dentry *dentry)
 	if (S_ISLNK(inode->i_mode))
 		return -EOPNOTSUPP;
 
-	return posix_acl_chmod(mnt_userns, dentry, inode->i_mode);
+	return posix_acl_chmod(idmap, dentry, inode->i_mode);
 }
 
 /*