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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2005-2020 Junjiro R. Okajima
*
* This program, aufs is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* sub-routines for dentry cache
*/
#ifndef __AUFS_DCSUB_H__
#define __AUFS_DCSUB_H__
#ifdef __KERNEL__
#include <linux/dcache.h>
#include <linux/fs.h>
struct au_dpage {
int ndentry;
struct dentry **dentries;
};
struct au_dcsub_pages {
int ndpage;
struct au_dpage *dpages;
};
/* ---------------------------------------------------------------------- */
/* dcsub.c */
int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp);
void au_dpages_free(struct au_dcsub_pages *dpages);
typedef int (*au_dpages_test)(struct dentry *dentry, void *arg);
int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
au_dpages_test test, void *arg);
int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
int do_include, au_dpages_test test, void *arg);
int au_dcsub_pages_rev_aufs(struct au_dcsub_pages *dpages,
struct dentry *dentry, int do_include);
int au_test_subdir(struct dentry *d1, struct dentry *d2);
/* ---------------------------------------------------------------------- */
/*
* todo: in linux-3.13, several similar (but faster) helpers are added to
* include/linux/dcache.h. Try them (in the future).
*/
static inline int au_d_hashed_positive(struct dentry *d)
{
int err;
struct inode *inode = d_inode(d);
err = 0;
if (unlikely(d_unhashed(d)
|| d_is_negative(d)
|| !inode->i_nlink))
err = -ENOENT;
return err;
}
static inline int au_d_linkable(struct dentry *d)
{
int err;
struct inode *inode = d_inode(d);
err = au_d_hashed_positive(d);
if (err
&& d_is_positive(d)
&& (inode->i_state & I_LINKABLE))
err = 0;
return err;
}
static inline int au_d_alive(struct dentry *d)
{
int err;
struct inode *inode;
err = 0;
if (!IS_ROOT(d))
err = au_d_hashed_positive(d);
else {
inode = d_inode(d);
if (unlikely(d_unlinked(d)
|| d_is_negative(d)
|| !inode->i_nlink))
err = -ENOENT;
}
return err;
}
static inline int au_alive_dir(struct dentry *d)
{
int err;
err = au_d_alive(d);
if (unlikely(err || IS_DEADDIR(d_inode(d))))
err = -ENOENT;
return err;
}
static inline int au_qstreq(struct qstr *a, struct qstr *b)
{
return a->len == b->len
&& !memcmp(a->name, b->name, a->len);
}
/*
* by the commit
* 360f547 2015-01-25 dcache: let the dentry count go down to zero without
* taking d_lock
* the type of d_lockref.count became int, but the inlined function d_count()
* still returns unsigned int.
* I don't know why. Maybe it is for every d_count() users?
* Anyway au_dcount() lives on.
*/
static inline int au_dcount(struct dentry *d)
{
return (int)d_count(d);
}
#endif /* __KERNEL__ */
#endif /* __AUFS_DCSUB_H__ */
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