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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/>.
*/
/*
* magic sysrq handler
*/
/* #include <linux/sysrq.h> */
#include <linux/writeback.h>
#include "aufs.h"
/* ---------------------------------------------------------------------- */
static void sysrq_sb(struct super_block *sb)
{
char *plevel;
struct au_sbinfo *sbinfo;
struct file *file;
struct hlist_bl_head *files;
struct hlist_bl_node *pos;
struct au_finfo *finfo;
struct inode *i;
plevel = au_plevel;
au_plevel = KERN_WARNING;
/* since we define pr_fmt, call printk directly */
#define pr(str) printk(KERN_WARNING AUFS_NAME ": " str)
sbinfo = au_sbi(sb);
printk(KERN_WARNING "si=%lx\n", sysaufs_si_id(sbinfo));
pr("superblock\n");
au_dpri_sb(sb);
#if 0 /* reserved */
do {
int err, i, j, ndentry;
struct au_dcsub_pages dpages;
struct au_dpage *dpage;
err = au_dpages_init(&dpages, GFP_ATOMIC);
if (unlikely(err))
break;
err = au_dcsub_pages(&dpages, sb->s_root, NULL, NULL);
if (!err)
for (i = 0; i < dpages.ndpage; i++) {
dpage = dpages.dpages + i;
ndentry = dpage->ndentry;
for (j = 0; j < ndentry; j++)
au_dpri_dentry(dpage->dentries[j]);
}
au_dpages_free(&dpages);
} while (0);
#endif
pr("isolated inode\n");
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry(i, &sb->s_inodes, i_sb_list) {
spin_lock(&i->i_lock);
if (hlist_empty(&i->i_dentry))
au_dpri_inode(i);
spin_unlock(&i->i_lock);
}
spin_unlock(&sb->s_inode_list_lock);
pr("files\n");
files = &au_sbi(sb)->si_files;
hlist_bl_lock(files);
hlist_bl_for_each_entry(finfo, pos, files, fi_hlist) {
umode_t mode;
file = finfo->fi_file;
mode = file_inode(file)->i_mode;
if (!special_file(mode))
au_dpri_file(file);
}
hlist_bl_unlock(files);
pr("done\n");
#undef pr
au_plevel = plevel;
}
/* ---------------------------------------------------------------------- */
/* module parameter */
static char *aufs_sysrq_key = "a";
module_param_named(sysrq, aufs_sysrq_key, charp, 0444);
MODULE_PARM_DESC(sysrq, "MagicSysRq key for " AUFS_NAME);
static void au_sysrq(int key __maybe_unused)
{
struct au_sbinfo *sbinfo;
struct hlist_bl_node *pos;
lockdep_off();
au_sbilist_lock();
hlist_bl_for_each_entry(sbinfo, pos, &au_sbilist, si_list)
sysrq_sb(sbinfo->si_sb);
au_sbilist_unlock();
lockdep_on();
}
static struct sysrq_key_op au_sysrq_op = {
.handler = au_sysrq,
.help_msg = "Aufs",
.action_msg = "Aufs",
.enable_mask = SYSRQ_ENABLE_DUMP
};
/* ---------------------------------------------------------------------- */
int __init au_sysrq_init(void)
{
int err;
char key;
err = -1;
key = *aufs_sysrq_key;
if ('a' <= key && key <= 'z')
err = register_sysrq_key(key, &au_sysrq_op);
if (unlikely(err))
pr_err("err %d, sysrq=%c\n", err, key);
return err;
}
void au_sysrq_fin(void)
{
int err;
err = unregister_sysrq_key(*aufs_sysrq_key, &au_sysrq_op);
if (unlikely(err))
pr_err("err %d (ignored)\n", err);
}
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