fs: port ->permission() 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, 5 insertions, 5 deletions

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 972a8333317f..7acc89f47a5a 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1335,7 +1335,7 @@ bail:
 	return err;
 }
 
-int ocfs2_permission(struct user_namespace *mnt_userns, struct inode *inode,
+int ocfs2_permission(struct mnt_idmap *idmap, struct inode *inode,
 		     int mask)
 {
 	int ret, had_lock;
@@ -1361,7 +1361,7 @@ int ocfs2_permission(struct user_namespace *mnt_userns, struct inode *inode,
 		dump_stack();
 	}
 
-	ret = generic_permission(&init_user_ns, inode, mask);
+	ret = generic_permission(&nop_mnt_idmap, inode, mask);
 
 	ocfs2_inode_unlock_tracker(inode, 0, &oh, had_lock);
 out:
diff --git a/fs/ocfs2/file.h b/fs/ocfs2/file.h
index ddc76aaffe79..8e53e4ac1120 100644
--- a/fs/ocfs2/file.h
+++ b/fs/ocfs2/file.h
@@ -53,7 +53,7 @@ int ocfs2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		  struct iattr *attr);
 int ocfs2_getattr(struct mnt_idmap *idmap, const struct path *path,
 		  struct kstat *stat, u32 request_mask, unsigned int flags);
-int ocfs2_permission(struct user_namespace *mnt_userns,
+int ocfs2_permission(struct mnt_idmap *idmap,
 		     struct inode *inode,
 		     int mask);
 
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 623db358b1ef..5a656dc683f1 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -4316,7 +4316,7 @@ static inline int ocfs2_may_create(struct inode *dir, struct dentry *child)
 		return -EEXIST;
 	if (IS_DEADDIR(dir))
 		return -ENOENT;
-	return inode_permission(&init_user_ns, dir, MAY_WRITE | MAY_EXEC);
+	return inode_permission(&nop_mnt_idmap, dir, MAY_WRITE | MAY_EXEC);
 }
 
 /**
@@ -4370,7 +4370,7 @@ static int ocfs2_vfs_reflink(struct dentry *old_dentry, struct inode *dir,
 	 * file.
 	 */
 	if (!preserve) {
-		error = inode_permission(&init_user_ns, inode, MAY_READ);
+		error = inode_permission(&nop_mnt_idmap, inode, MAY_READ);
 		if (error)
 			return error;
 	}