[mirror_ubuntu-bionic-kernel.git] / fs / aufs / dcsub.h

/*
 * Copyright (C) 2005-2017 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__ */
Commit	Line	Data
eea4740f SF	1	/*
	2	* Copyright (C) 2005-2017 Junjiro R. Okajima
	3	*
	4	* This program, aufs is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation; either version 2 of the License, or
	7	* (at your option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	16	*/
	17
	18	/*
	19	* sub-routines for dentry cache
	20	*/
	21
	22	#ifndef __AUFS_DCSUB_H__
	23	#define __AUFS_DCSUB_H__
	24
	25	#ifdef __KERNEL__
	26
	27	#include <linux/dcache.h>
	28	#include <linux/fs.h>
	29
	30	struct au_dpage {
	31	int ndentry;
	32	struct dentry **dentries;
	33	};
	34
	35	struct au_dcsub_pages {
	36	int ndpage;
	37	struct au_dpage *dpages;
	38	};
	39
	40	/* ---------------------------------------------------------------------- */
	41
	42	/* dcsub.c */
	43	int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp);
	44	void au_dpages_free(struct au_dcsub_pages *dpages);
	45	typedef int (au_dpages_test)(struct dentry dentry, void *arg);
	46	int au_dcsub_pages(struct au_dcsub_pages dpages, struct dentry root,
	47	au_dpages_test test, void *arg);
	48	int au_dcsub_pages_rev(struct au_dcsub_pages dpages, struct dentry dentry,
	49	int do_include, au_dpages_test test, void *arg);
	50	int au_dcsub_pages_rev_aufs(struct au_dcsub_pages *dpages,
	51	struct dentry *dentry, int do_include);
	52	int au_test_subdir(struct dentry d1, struct dentry d2);
	53
	54	/* ---------------------------------------------------------------------- */
	55
	56	/*
	57	* todo: in linux-3.13, several similar (but faster) helpers are added to
	58	* include/linux/dcache.h. Try them (in the future).
	59	*/
	60
	61	static inline int au_d_hashed_positive(struct dentry *d)
	62	{
	63	int err;
	64	struct inode *inode = d_inode(d);
65
66	err = 0;
67	if (unlikely(d_unhashed(d)
68	\|\| d_is_negative(d)
69	\|\| !inode->i_nlink))
70	err = -ENOENT;
71	return err;
72	}
73
74	static inline int au_d_linkable(struct dentry *d)
75	{
76	int err;
77	struct inode *inode = d_inode(d);
78
79	err = au_d_hashed_positive(d);
80	if (err
81	&& d_is_positive(d)
82	&& (inode->i_state & I_LINKABLE))
83	err = 0;
84	return err;
85	}
86
87	static inline int au_d_alive(struct dentry *d)
88	{
89	int err;
90	struct inode *inode;
91
92	err = 0;
93	if (!IS_ROOT(d))
94	err = au_d_hashed_positive(d);
95	else {
96	inode = d_inode(d);
97	if (unlikely(d_unlinked(d)
98	\|\| d_is_negative(d)
99	\|\| !inode->i_nlink))
100	err = -ENOENT;
101	}
102	return err;
103	}
104
105	static inline int au_alive_dir(struct dentry *d)
106	{
107	int err;
108
109	err = au_d_alive(d);
110	if (unlikely(err \|\| IS_DEADDIR(d_inode(d))))
111	err = -ENOENT;
112	return err;
113	}
114
115	static inline int au_qstreq(struct qstr a, struct qstr b)
116	{
117	return a->len == b->len
118	&& !memcmp(a->name, b->name, a->len);
119	}
120
121	/*
122	* by the commit
123	* 360f547 2015-01-25 dcache: let the dentry count go down to zero without
124	* taking d_lock
125	* the type of d_lockref.count became int, but the inlined function d_count()
126	* still returns unsigned int.
127	* I don't know why. Maybe it is for every d_count() users?
128	* Anyway au_dcount() lives on.
129	*/
130	static inline int au_dcount(struct dentry *d)
131	{
132	return (int)d_count(d);
133	}
134
135	#endif /* __KERNEL__ */
136	#endif /* __AUFS_DCSUB_H__ */