vfs: export __inode_permission() to modules

We need to be able to check inode permissions (but not filesystem implied
permissions) for stackable filesystems.  Expose this interface for overlayfs.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

fs/internal.h

@@ -47,7 +47,6 @@ extern void __init chrdev_init(void);
 /*
  * namei.c
  */
-extern int __inode_permission(struct inode *, int);
 extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct path *);

fs/namei.c

@@ -416,6 +416,7 @@ int __inode_permission(struct inode *inode, int mask)
 
 	return security_inode_permission(inode, mask);
 }
+EXPORT_SYMBOL(__inode_permission);
 
 /**
  * sb_permission - Check superblock-level permissions

include/linux/fs.h

@@ -2257,6 +2257,7 @@ extern sector_t bmap(struct inode *, sector_t);
 #endif
 extern int notify_change(struct dentry *, struct iattr *, struct inode **);
 extern int inode_permission(struct inode *, int);
+extern int __inode_permission(struct inode *, int);
 extern int generic_permission(struct inode *, int);
 
 static inline bool execute_ok(struct inode *inode)