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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
*/
#include "aufs.h"
static void au_dpage_free(struct au_dpage *dpage)
{
int i;
struct dentry **p;
p = dpage->dentries;
for (i = 0; i < dpage->ndentry; i++)
dput(*p++);
free_page((unsigned long)dpage->dentries);
}
int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp)
{
int err;
void *p;
err = -ENOMEM;
dpages->dpages = kmalloc(sizeof(*dpages->dpages), gfp);
if (unlikely(!dpages->dpages))
goto out;
p = (void *)__get_free_page(gfp);
if (unlikely(!p))
goto out_dpages;
dpages->dpages[0].ndentry = 0;
dpages->dpages[0].dentries = p;
dpages->ndpage = 1;
return 0; /* success */
out_dpages:
au_kfree_try_rcu(dpages->dpages);
out:
return err;
}
void au_dpages_free(struct au_dcsub_pages *dpages)
{
int i;
struct au_dpage *p;
p = dpages->dpages;
for (i = 0; i < dpages->ndpage; i++)
au_dpage_free(p++);
au_kfree_try_rcu(dpages->dpages);
}
static int au_dpages_append(struct au_dcsub_pages *dpages,
struct dentry *dentry, gfp_t gfp)
{
int err, sz;
struct au_dpage *dpage;
void *p;
dpage = dpages->dpages + dpages->ndpage - 1;
sz = PAGE_SIZE / sizeof(dentry);
if (unlikely(dpage->ndentry >= sz)) {
AuLabel(new dpage);
err = -ENOMEM;
sz = dpages->ndpage * sizeof(*dpages->dpages);
p = au_kzrealloc(dpages->dpages, sz,
sz + sizeof(*dpages->dpages), gfp,
/*may_shrink*/0);
if (unlikely(!p))
goto out;
dpages->dpages = p;
dpage = dpages->dpages + dpages->ndpage;
p = (void *)__get_free_page(gfp);
if (unlikely(!p))
goto out;
dpage->ndentry = 0;
dpage->dentries = p;
dpages->ndpage++;
}
AuDebugOn(au_dcount(dentry) <= 0);
dpage->dentries[dpage->ndentry++] = dget_dlock(dentry);
return 0; /* success */
out:
return err;
}
/* todo: BAD approach */
/* copied from linux/fs/dcache.c */
enum d_walk_ret {
D_WALK_CONTINUE,
D_WALK_QUIT,
D_WALK_NORETRY,
D_WALK_SKIP,
};
extern void d_walk(struct dentry *parent, void *data,
enum d_walk_ret (*enter)(void *, struct dentry *));
struct ac_dpages_arg {
int err;
struct au_dcsub_pages *dpages;
struct super_block *sb;
au_dpages_test test;
void *arg;
};
static enum d_walk_ret au_call_dpages_append(void *_arg, struct dentry *dentry)
{
enum d_walk_ret ret;
struct ac_dpages_arg *arg = _arg;
ret = D_WALK_CONTINUE;
if (dentry->d_sb == arg->sb
&& !IS_ROOT(dentry)
&& au_dcount(dentry) > 0
&& au_di(dentry)
&& (!arg->test || arg->test(dentry, arg->arg))) {
arg->err = au_dpages_append(arg->dpages, dentry, GFP_ATOMIC);
if (unlikely(arg->err))
ret = D_WALK_QUIT;
}
return ret;
}
int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
au_dpages_test test, void *arg)
{
struct ac_dpages_arg args = {
.err = 0,
.dpages = dpages,
.sb = root->d_sb,
.test = test,
.arg = arg
};
d_walk(root, &args, au_call_dpages_append);
return args.err;
}
int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
int do_include, au_dpages_test test, void *arg)
{
int err;
err = 0;
write_seqlock(&rename_lock);
spin_lock(&dentry->d_lock);
if (do_include
&& au_dcount(dentry) > 0
&& (!test || test(dentry, arg)))
err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
spin_unlock(&dentry->d_lock);
if (unlikely(err))
goto out;
/*
* RCU for vfsmount is unnecessary since this is a traverse in a single
* mount
*/
while (!IS_ROOT(dentry)) {
dentry = dentry->d_parent; /* rename_lock is locked */
spin_lock(&dentry->d_lock);
if (au_dcount(dentry) > 0
&& (!test || test(dentry, arg)))
err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
spin_unlock(&dentry->d_lock);
if (unlikely(err))
break;
}
out:
write_sequnlock(&rename_lock);
return err;
}
static inline int au_dcsub_dpages_aufs(struct dentry *dentry, void *arg)
{
return au_di(dentry) && dentry->d_sb == arg;
}
int au_dcsub_pages_rev_aufs(struct au_dcsub_pages *dpages,
struct dentry *dentry, int do_include)
{
return au_dcsub_pages_rev(dpages, dentry, do_include,
au_dcsub_dpages_aufs, dentry->d_sb);
}
int au_test_subdir(struct dentry *d1, struct dentry *d2)
{
struct path path[2] = {
{
.dentry = d1
},
{
.dentry = d2
}
};
return path_is_under(path + 0, path + 1);
}
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