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/*
* Copyright (c) 2003-2009 Erez Zadok
* Copyright (c) 2003-2006 Charles P. Wright
* Copyright (c) 2005-2007 Josef 'Jeff' Sipek
* Copyright (c) 2005-2006 Junjiro Okajima
* Copyright (c) 2005 Arun M. Krishnakumar
* Copyright (c) 2004-2006 David P. Quigley
* Copyright (c) 2003-2004 Mohammad Nayyer Zubair
* Copyright (c) 2003 Puja Gupta
* Copyright (c) 2003 Harikesavan Krishnan
* Copyright (c) 2003-2009 Stony Brook University
* Copyright (c) 2003-2009 The Research Foundation of SUNY
*
* 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 "union.h"
#define RD_NONE 0
#define RD_CHECK_EMPTY 1
/* The callback structure for check_empty. */
struct unionfs_rdutil_callback {
int err;
int filldir_called;
struct unionfs_dir_state *rdstate;
int mode;
};
/* This filldir function makes sure only whiteouts exist within a directory. */
static int readdir_util_callback(void *dirent, const char *oname, int namelen,
loff_t offset, u64 ino, unsigned int d_type)
{
int err = 0;
struct unionfs_rdutil_callback *buf = dirent;
int is_whiteout;
struct filldir_node *found;
char *name = (char *) oname;
buf->filldir_called = 1;
if (name[0] == '.' && (namelen == 1 ||
(name[1] == '.' && namelen == 2)))
goto out;
is_whiteout = is_whiteout_name(&name, &namelen);
found = find_filldir_node(buf->rdstate, name, namelen, is_whiteout);
/* If it was found in the table there was a previous whiteout. */
if (found)
goto out;
/*
* if it wasn't found and isn't a whiteout, the directory isn't
* empty.
*/
err = -ENOTEMPTY;
if ((buf->mode == RD_CHECK_EMPTY) && !is_whiteout)
goto out;
err = add_filldir_node(buf->rdstate, name, namelen,
buf->rdstate->bindex, is_whiteout);
out:
buf->err = err;
return err;
}
/* Is a directory logically empty? */
int check_empty(struct dentry *dentry, struct dentry *parent,
struct unionfs_dir_state **namelist)
{
int err = 0;
struct dentry *lower_dentry = NULL;
struct vfsmount *mnt;
struct super_block *sb;
struct file *lower_file;
struct unionfs_rdutil_callback *buf = NULL;
int bindex, bstart, bend, bopaque;
sb = dentry->d_sb;
BUG_ON(!S_ISDIR(dentry->d_inode->i_mode));
err = unionfs_partial_lookup(dentry, parent);
if (err)
goto out;
bstart = dbstart(dentry);
bend = dbend(dentry);
bopaque = dbopaque(dentry);
if (0 <= bopaque && bopaque < bend)
bend = bopaque;
buf = kmalloc(sizeof(struct unionfs_rdutil_callback), GFP_KERNEL);
if (unlikely(!buf)) {
err = -ENOMEM;
goto out;
}
buf->err = 0;
buf->mode = RD_CHECK_EMPTY;
buf->rdstate = alloc_rdstate(dentry->d_inode, bstart);
if (unlikely(!buf->rdstate)) {
err = -ENOMEM;
goto out;
}
/* Process the lower directories with rdutil_callback as a filldir. */
for (bindex = bstart; bindex <= bend; bindex++) {
lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
if (!lower_dentry)
continue;
if (!lower_dentry->d_inode)
continue;
if (!S_ISDIR(lower_dentry->d_inode->i_mode))
continue;
dget(lower_dentry);
mnt = unionfs_mntget(dentry, bindex);
branchget(sb, bindex);
lower_file = dentry_open(lower_dentry, mnt, O_RDONLY);
if (IS_ERR(lower_file)) {
err = PTR_ERR(lower_file);
branchput(sb, bindex);
goto out;
}
do {
buf->filldir_called = 0;
buf->rdstate->bindex = bindex;
err = vfs_readdir(lower_file,
readdir_util_callback, buf);
if (buf->err)
err = buf->err;
} while ((err >= 0) && buf->filldir_called);
/* fput calls dput for lower_dentry */
fput(lower_file);
branchput(sb, bindex);
if (err < 0)
goto out;
}
out:
if (buf) {
if (namelist && !err)
*namelist = buf->rdstate;
else if (buf->rdstate)
free_rdstate(buf->rdstate);
kfree(buf);
}
return err;
}
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