ntfs3: rework xattr handlers and switch to POSIX ACL VFS helpers

[ Upstream commit a26aa12 ]

The xattr code in ntfs3 is currently a bit confused. For example, it
defines a POSIX ACL i_op->set_acl() method but instead of relying on the
generic POSIX ACL VFS helpers it defines its own set of xattr helpers
with the consequence that i_op->set_acl() is currently dead code.

Switch ntfs3 to rely on the VFS POSIX ACL xattr handlers. Also remove
i_op->{g,s}et_acl() methods from symlink inode operations. Symlinks
don't support xattrs.

This is a preliminary change for the following patches which move
handling idmapped mounts directly in posix_acl_xattr_set().

This survives POSIX ACL xfstests.

Fixes: be71b5c ("fs/ntfs3: Add attrib operations")
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>>
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs/ntfs3/inode.c

@@ -1927,8 +1927,6 @@ const struct inode_operations ntfs_link_inode_operations = {
 	.setattr	= ntfs3_setattr,
 	.listxattr	= ntfs_listxattr,
 	.permission	= ntfs_permission,
-	.get_acl	= ntfs_get_acl,
-	.set_acl	= ntfs_set_acl,
 };
 
 const struct address_space_operations ntfs_aops = {

fs/ntfs3/xattr.c

@@ -625,67 +625,6 @@ int ntfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 	return ntfs_set_acl_ex(mnt_userns, inode, acl, type, false);
 }
 
-static int ntfs_xattr_get_acl(struct user_namespace *mnt_userns,
-			      struct inode *inode, int type, void *buffer,
-			      size_t size)
-{
-	struct posix_acl *acl;
-	int err;
-
-	if (!(inode->i_sb->s_flags & SB_POSIXACL)) {
-		ntfs_inode_warn(inode, "add mount option \"acl\" to use acl");
-		return -EOPNOTSUPP;
-	}
-
-	acl = ntfs_get_acl(inode, type, false);
-	if (IS_ERR(acl))
-		return PTR_ERR(acl);
-
-	if (!acl)
-		return -ENODATA;
-
-	err = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
-	posix_acl_release(acl);
-
-	return err;
-}
-
-static int ntfs_xattr_set_acl(struct user_namespace *mnt_userns,
-			      struct inode *inode, int type, const void *value,
-			      size_t size)
-{
-	struct posix_acl *acl;
-	int err;
-
-	if (!(inode->i_sb->s_flags & SB_POSIXACL)) {
-		ntfs_inode_warn(inode, "add mount option \"acl\" to use acl");
-		return -EOPNOTSUPP;
-	}
-
-	if (!inode_owner_or_capable(mnt_userns, inode))
-		return -EPERM;
-
-	if (!value) {
-		acl = NULL;
-	} else {
-		acl = posix_acl_from_xattr(&init_user_ns, value, size);
-		if (IS_ERR(acl))
-			return PTR_ERR(acl);
-
-		if (acl) {
-			err = posix_acl_valid(&init_user_ns, acl);
-			if (err)
-				goto release_and_out;
-		}
-	}
-
-	err = ntfs_set_acl(mnt_userns, inode, acl, type);
-
-release_and_out:
-	posix_acl_release(acl);
-	return err;
-}
-
 /*
  * ntfs_init_acl - Initialize the ACLs of a new inode.
  *
@@ -852,23 +791,6 @@ static int ntfs_getxattr(const struct xattr_handler *handler, struct dentry *de,
 		goto out;
 	}
 
-#ifdef CONFIG_NTFS3_FS_POSIX_ACL
-	if ((name_len == sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1 &&
-	     !memcmp(name, XATTR_NAME_POSIX_ACL_ACCESS,
-		     sizeof(XATTR_NAME_POSIX_ACL_ACCESS))) ||
-	    (name_len == sizeof(XATTR_NAME_POSIX_ACL_DEFAULT) - 1 &&
-	     !memcmp(name, XATTR_NAME_POSIX_ACL_DEFAULT,
-		     sizeof(XATTR_NAME_POSIX_ACL_DEFAULT)))) {
-		/* TODO: init_user_ns? */
-		err = ntfs_xattr_get_acl(
-			&init_user_ns, inode,
-			name_len == sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1
-				? ACL_TYPE_ACCESS
-				: ACL_TYPE_DEFAULT,
-			buffer, size);
-		goto out;
-	}
-#endif
 	/* Deal with NTFS extended attribute. */
 	err = ntfs_get_ea(inode, name, name_len, buffer, size, NULL);
 
@@ -981,22 +903,6 @@ static noinline int ntfs_setxattr(const struct xattr_handler *handler,
 		goto out;
 	}
 
-#ifdef CONFIG_NTFS3_FS_POSIX_ACL
-	if ((name_len == sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1 &&
-	     !memcmp(name, XATTR_NAME_POSIX_ACL_ACCESS,
-		     sizeof(XATTR_NAME_POSIX_ACL_ACCESS))) ||
-	    (name_len == sizeof(XATTR_NAME_POSIX_ACL_DEFAULT) - 1 &&
-	     !memcmp(name, XATTR_NAME_POSIX_ACL_DEFAULT,
-		     sizeof(XATTR_NAME_POSIX_ACL_DEFAULT)))) {
-		err = ntfs_xattr_set_acl(
-			mnt_userns, inode,
-			name_len == sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1
-				? ACL_TYPE_ACCESS
-				: ACL_TYPE_DEFAULT,
-			value, size);
-		goto out;
-	}
-#endif
 	/* Deal with NTFS extended attribute. */
 	err = ntfs_set_ea(inode, name, name_len, value, size, flags, 0);
 
@@ -1086,15 +992,19 @@ static bool ntfs_xattr_user_list(struct dentry *dentry)
 }
 
 // clang-format off
-static const struct xattr_handler ntfs_xattr_handler = {
+static const struct xattr_handler ntfs_other_xattr_handler = {
 	.prefix	= "",
 	.get	= ntfs_getxattr,
 	.set	= ntfs_setxattr,
 	.list	= ntfs_xattr_user_list,
 };
 
 const struct xattr_handler *ntfs_xattr_handlers[] = {
-	&ntfs_xattr_handler,
+#ifdef CONFIG_NTFS3_FS_POSIX_ACL
+	&posix_acl_access_xattr_handler,
+	&posix_acl_default_xattr_handler,
+#endif
+	&ntfs_other_xattr_handler,
 	NULL,
 };
 // clang-format on