/*
*
* Copyright (C) 2011 Novell Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/file.h>
#include <linux/xattr.h>
#include <linux/rbtree.h>
#include <linux/security.h>
#include <linux/cred.h>
#include <linux/ratelimit.h>
#include "overlayfs.h"
struct ovl_cache_entry {
unsigned int len;
unsigned int type;
u64 real_ino;
u64 ino;
struct list_head l_node;
struct rb_node node;
struct ovl_cache_entry *next_maybe_whiteout;
bool is_upper;
bool is_whiteout;
char name[];
};
struct ovl_dir_cache {
long refcount;
u64 version;
struct list_head entries;
struct rb_root root;
};
struct ovl_readdir_data {
struct dir_context ctx;
struct dentry *dentry;
bool is_lowest;
struct rb_root *root;
struct list_head *list;
struct list_head middle;
struct ovl_cache_entry *first_maybe_whiteout;
int count;
int err;
bool is_upper;
bool d_type_supported;
};
struct ovl_dir_file {
bool is_real;
bool is_upper;
struct ovl_dir_cache *cache;
struct list_head *cursor;
struct file *realfile;
struct file *upperfile;
};
static struct ovl_cache_entry *ovl_cache_entry_from_node(struct rb_node *n)
{
return rb_entry(n, struct ovl_cache_entry, node);
}
static bool ovl_cache_entry_find_link(const char *name, int len,
struct rb_node ***link,
struct rb_node **parent)
{
bool found = false;
struct rb_node **newp = *link;
while (!found && *newp) {
int cmp;
struct ovl_cache_entry *tmp;
*parent = *newp;
tmp = ovl_cache_entry_from_node(*newp);
cmp = strncmp(name, tmp->name, len);
if (cmp > 0)
newp = &tmp->node.rb_right;
else if (cmp < 0 || len < tmp->len)
newp = &tmp->node.rb_left;
else
found = true;
}
*link = newp;
return found;
}
static struct ovl_cache_entry *ovl_cache_entry_find(struct rb_root *root,
const char *name, int len)
{
struct rb_node *node = root->rb_node;
int cmp;
while (node) {
struct ovl_cache_entry *p = ovl_cache_entry_from_node(node);
cmp = strncmp(name, p->name, len);
if (cmp > 0)
node = p->node.rb_right;
else if (cmp < 0 || len < p->len)
node = p->node.rb_left;
else
return p;
}
return NULL;
}
static bool ovl_calc_d_ino(struct ovl_readdir_data *rdd,
struct ovl_cache_entry *p)
{
/* Don't care if not doing ovl_iter() */
if (!rdd->dentry)
return false;
/* Always recalc d_ino for parent */
if (strcmp(p->name, "..") == 0)
return true;
/* If this is lower, then native d_ino will do */
if (!rdd->is_upper)
return false;
/*
* Recalc d_ino for '.' and for all entries if dir is impure (contains
* copied up entries)
*/
if ((p->name[0] == '.' &&