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/*
* Copyright (c) 2003-2006 Erez Zadok
* Copyright (c) 2003-2006 Charles P. Wright
* Copyright (c) 2005-2006 Josef 'Jeff' Sipek
* Copyright (c) 2005-2006 Junjiro Okajima
* Copyright (c) 2005 Arun M. Krishnakumar
* Copyright (c) 2005-2006 David P. Quigley
* Copyright (c) 2003-2004 Mohammad Nayyer Zubair
* Copyright (c) 2003 Puja Gupta
* Copyright (c) 2003 Harikesavan Krishnan
* Copyright (c) 2003-2006 Stony Brook University
* Copyright (c) 2003-2006 The Research Foundation of State University of New York
*
* For specific licensing information, see the COPYING file distributed with
* this package.
*
* This Copyright notice must be kept intact and distributed with all sources.
*/
/*
* $Id: subr.c,v 1.142 2006/09/21 18:19:36 jsipek Exp $
*/
#include "unionfs.h"
#include <linux/security.h>
/* Pass an unionfs dentry and an index. It will try to create a whiteout
* for the filename in dentry, and will try in branch 'index'. On error,
* it will proceed to a branch to the left.
*/
int create_whiteout(struct dentry *dentry, int start)
{
int bstart, bend, bindex;
struct dentry *hidden_dir_dentry;
struct dentry *hidden_dentry;
struct dentry *hidden_wh_dentry;
char *name = NULL;
int err = -EINVAL;
print_entry("start = %d", start);
verify_locked(dentry);
print_dentry("IN create_whiteout", dentry);
bstart = dbstart(dentry);
bend = dbend(dentry);
/* create dentry's whiteout equivalent */
name = alloc_whname(dentry->d_name.name, dentry->d_name.len);
if (IS_ERR(name)) {
err = PTR_ERR(name);
goto out;
}
for (bindex = start; bindex >= 0; bindex--) {
hidden_dentry = dtohd_index(dentry, bindex);
if (!hidden_dentry) {
/* if hidden dentry is not present, create the entire
* hidden dentry directory structure and go ahead.
* Since we want to just create whiteout, we only want
* the parent dentry, and hence get rid of this dentry.
*/
hidden_dentry = create_parents(dentry->d_inode,
dentry, bindex);
if (!hidden_dentry || IS_ERR(hidden_dentry)) {
dprint(PRINT_DEBUG_WHITEOUT,
"create_parents failed for bindex = %d\n",
bindex);
continue;
}
}
hidden_wh_dentry =
LOOKUP_ONE_LEN(name, hidden_dentry->d_parent,
dentry->d_name.len + WHLEN);
if (IS_ERR(hidden_wh_dentry))
continue;
/* The whiteout already exists. This used to be impossible, but
* now is possible because of opaqueness. */
if (hidden_wh_dentry->d_inode) {
DPUT(hidden_wh_dentry);
err = 0;
goto out;
}
hidden_dir_dentry = lock_parent(hidden_wh_dentry);
if (!(err = is_robranch_super(dentry->d_sb, bindex))) {
err =
vfs_create(hidden_dir_dentry->d_inode,
hidden_wh_dentry,
~current->fs->umask & S_IRWXUGO, NULL);
}
unlock_dir(hidden_dir_dentry);
DPUT(hidden_wh_dentry);
if (!err)
break;
if (!IS_COPYUP_ERR(err))
break;
}
/* set dbopaque so that lookup will not proceed after this branch */
if (!err)
set_dbopaque(dentry, bindex);
print_dentry("OUT create_whiteout", dentry);
out:
KFREE(name);
print_exit_status(err);
return err;
}
/* This is a helper function for rename, which ends up with hosed over dentries
* when it needs to revert. */
int unionfs_refresh_hidden_dentry(struct dentry *dentry, int bindex)
{
struct dentry *hidden_dentry;
struct dentry *hidden_parent;
int err = 0;
print_entry(" bindex = %d", bindex);
verify_locked(dentry);
lock_dentry(dentry->d_parent);
hidden_parent = dtohd_index(dentry->d_parent, bindex);
unlock_dentry(dentry->d_parent);
BUG_ON(!S_ISDIR(hidden_parent->d_inode->i_mode));
hidden_dentry =
LOOKUP_ONE_LEN(dentry->d_name.name, hidden_parent,
dentry->d_name.len);
if (IS_ERR(hidden_dentry)) {
err = PTR_ERR(hidden_dentry);
goto out;
}
if (dtohd_index(dentry, bindex))
DPUT(dtohd_index(dentry, bindex));
if (itohi_index(dentry->d_inode, bindex)) {
IPUT(itohi_index(dentry->d_inode, bindex));
set_itohi_index(dentry->d_inode, bindex, NULL);
}
if (!hidden_dentry->d_inode) {
DPUT(hidden_dentry);
set_dtohd_index(dentry, bindex, NULL);
} else {
set_dtohd_index(dentry, bindex, hidden_dentry);
set_itohi_index(dentry->d_inode, bindex,
IGRAB(hidden_dentry->d_inode));
}
out:
print_exit_status(err);
return err;
}
int make_dir_opaque(struct dentry *dentry, int bindex)
{
int err;
struct dentry *hidden_dentry, *diropq;
struct inode *hidden_dir;
hidden_dentry = dtohd_index(dentry, bindex);
hidden_dir = hidden_dentry->d_inode;
BUG_ON(!S_ISDIR(dentry->d_inode->i_mode)
|| !S_ISDIR(hidden_dir->i_mode));
mutex_lock(&hidden_dir->i_mutex);
diropq = LOOKUP_ONE_LEN(UNIONFS_DIR_OPAQUE, hidden_dentry,
sizeof(UNIONFS_DIR_OPAQUE) - 1);
err = PTR_ERR(diropq);
if (IS_ERR(diropq))
goto out;
err = 0;
if (!diropq->d_inode)
err = vfs_create(hidden_dir, diropq, S_IRUGO, NULL);
DPUT(diropq);
if (!err)
set_dbopaque(dentry, bindex);
out:
mutex_unlock(&hidden_dir->i_mutex);
return err;
}
/*
*
* vim:shiftwidth=8
* vim:tabstop=8
*
* For Emacs:
* Local variables:
* c-basic-offset: 8
* c-comment-only-line-offset: 0
* c-offsets-alist: ((statement-block-intro . +) (knr-argdecl-intro . 0)
* (substatement-open . 0) (label . 0) (statement-cont . +))
* indent-tabs-mode: t
* tab-width: 8
* End:
*/
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