suse man page for inode_permission

INODE_PERMISSION(9)						   The Linux VFS					       INODE_PERMISSION(9)

NAME
       inode_permission - check for access rights to a given inode

SYNOPSIS
       int inode_permission(struct inode * inode, int mask);

ARGUMENTS
       inode
	   inode to check permission on

       mask
	   right to check for (MAY_READ, MAY_WRITE, MAY_EXEC)

DESCRIPTION
       Used to check for read/write/execute permissions on an inode. We use "fsuid" for this, letting us set arbitrary permissions for filesystem
       access without changing the "normal" uids which are used for other things.

COPYRIGHT
Kernel Hackers Manual 2.6.					     July 2010						       INODE_PERMISSION(9)