/*
* fs/kernfs/dir.c - kernfs directory implementation
*
* Copyright (c) 2001-3 Patrick Mochel
* Copyright (c) 2007 SUSE Linux Products GmbH
* Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
*
* This file is released under the GPLv2.
*/
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/security.h>
#include <linux/hash.h>
#include "kernfs-internal.h"
DEFINE_MUTEX(kernfs_mutex);
static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */
static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by rename_lock */
#define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
static bool kernfs_active(struct kernfs_node *kn)
{
lockdep_assert_held(&kernfs_mutex);
return atomic_read(&kn->active) >= 0;
}
static bool kernfs_lockdep(struct kernfs_node *kn)
{
#ifdef CONFIG_DEBUG_LOCK_ALLOC
return kn->flags & KERNFS_LOCKDEP;
#else
return false;
#endif
}
static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen)
{
return strlcpy(buf, kn->parent ? kn->name : "/", buflen);
}
static char * __must_check kernfs_path_locked(struct kernfs_node *kn, char *buf,
size_t buflen)
{
char *p = buf + buflen;
int len;
*--p = '\0';
do {
len = strlen(kn->name);
if (p - 