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, 14 insertions, 14 deletions

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 62d6316e8066..bec75ed59c72 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -235,7 +235,7 @@ static int do_gfs2_set_flags(struct inode *inode, u32 reqflags, u32 mask)
 		goto out;
 
 	if (!IS_IMMUTABLE(inode)) {
-		error = gfs2_permission(&init_user_ns, inode, MAY_WRITE);
+		error = gfs2_permission(&nop_mnt_idmap, inode, MAY_WRITE);
 		if (error)
 			goto out;
 	}
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 0818d4e25d75..713efa3bb732 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -320,7 +320,7 @@ struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
 	}
 
 	if (!is_root) {
-		error = gfs2_permission(&init_user_ns, dir, MAY_EXEC);
+		error = gfs2_permission(&nop_mnt_idmap, dir, MAY_EXEC);
 		if (error)
 			goto out;
 	}
@@ -350,7 +350,7 @@ static int create_ok(struct gfs2_inode *dip, const struct qstr *name,
 {
 	int error;
 
-	error = gfs2_permission(&init_user_ns, &dip->i_inode,
+	error = gfs2_permission(&nop_mnt_idmap, &dip->i_inode,
 				MAY_WRITE | MAY_EXEC);
 	if (error)
 		return error;
@@ -960,7 +960,7 @@ static int gfs2_link(struct dentry *old_dentry, struct inode *dir,
 	if (inode->i_nlink == 0)
 		goto out_gunlock;
 
-	error = gfs2_permission(&init_user_ns, dir, MAY_WRITE | MAY_EXEC);
+	error = gfs2_permission(&nop_mnt_idmap, dir, MAY_WRITE | MAY_EXEC);
 	if (error)
 		goto out_gunlock;
 
@@ -1078,7 +1078,7 @@ static int gfs2_unlink_ok(struct gfs2_inode *dip, const struct qstr *name,
 	if (IS_APPEND(&dip->i_inode))
 		return -EPERM;
 
-	error = gfs2_permission(&init_user_ns, &dip->i_inode,
+	error = gfs2_permission(&nop_mnt_idmap, &dip->i_inode,
 				MAY_WRITE | MAY_EXEC);
 	if (error)
 		return error;
@@ -1504,7 +1504,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 			}
 		}
 	} else {
-		error = gfs2_permission(&init_user_ns, ndir,
+		error = gfs2_permission(&nop_mnt_idmap, ndir,
 					MAY_WRITE | MAY_EXEC);
 		if (error)
 			goto out_gunlock;
@@ -1541,7 +1541,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 	/* Check out the dir to be renamed */
 
 	if (dir_rename) {
-		error = gfs2_permission(&init_user_ns, d_inode(odentry),
+		error = gfs2_permission(&nop_mnt_idmap, d_inode(odentry),
 					MAY_WRITE);
 		if (error)
 			goto out_gunlock;
@@ -1705,13 +1705,13 @@ static int gfs2_exchange(struct inode *odir, struct dentry *odentry,
 		goto out_gunlock;
 
 	if (S_ISDIR(old_mode)) {
-		error = gfs2_permission(&init_user_ns, odentry->d_inode,
+		error = gfs2_permission(&nop_mnt_idmap, odentry->d_inode,
 					MAY_WRITE);
 		if (error)
 			goto out_gunlock;
 	}
 	if (S_ISDIR(new_mode)) {
-		error = gfs2_permission(&init_user_ns, ndentry->d_inode,
+		error = gfs2_permission(&nop_mnt_idmap, ndentry->d_inode,
 					MAY_WRITE);
 		if (error)
 			goto out_gunlock;
@@ -1841,7 +1841,7 @@ out:
 
 /**
  * gfs2_permission
- * @mnt_userns: User namespace of the mount the inode was found from
+ * @idmap: idmap of the mount the inode was found from
  * @inode: The inode
  * @mask: The mask to be tested
  *
@@ -1852,7 +1852,7 @@ out:
  * Returns: errno
  */
 
-int gfs2_permission(struct user_namespace *mnt_userns, struct inode *inode,
+int gfs2_permission(struct mnt_idmap *idmap, struct inode *inode,
 		    int mask)
 {
 	struct gfs2_inode *ip;
@@ -1872,7 +1872,7 @@ int gfs2_permission(struct user_namespace *mnt_userns, struct inode *inode,
 	if ((mask & MAY_WRITE) && IS_IMMUTABLE(inode))
 		error = -EPERM;
 	else
-		error = generic_permission(&init_user_ns, inode, mask);
+		error = generic_permission(&nop_mnt_idmap, inode, mask);
 	if (gfs2_holder_initialized(&i_gh))
 		gfs2_glock_dq_uninit(&i_gh);
 
@@ -1992,7 +1992,7 @@ static int gfs2_setattr(struct mnt_idmap *idmap,
 	if (error)
 		goto out;
 
-	error = may_setattr(&init_user_ns, inode, attr->ia_valid);
+	error = may_setattr(&nop_mnt_idmap, inode, attr->ia_valid);
 	if (error)
 		goto error;
 
diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
index bd0c64b65158..c8c5814e7295 100644
--- a/fs/gfs2/inode.h
+++ b/fs/gfs2/inode.h
@@ -99,7 +99,7 @@ extern int gfs2_inode_refresh(struct gfs2_inode *ip);
 
 extern struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
 				  int is_root);
-extern int gfs2_permission(struct user_namespace *mnt_userns,
+extern int gfs2_permission(struct mnt_idmap *idmap,
 			   struct inode *inode, int mask);
 extern struct inode *gfs2_lookup_simple(struct inode *dip, const char *name);
 extern void gfs2_dinode_out(const struct gfs2_inode *ip, void *buf);