fs/aufs/sysrq.c

   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  * magic sysrq hanlder
  20  */
  21
  22 /* #include <linux/sysrq.h> */
  23 #include <linux/writeback.h>
  24 #include "aufs.h"
  25
  26 /* ---------------------------------------------------------------------- */
  27
  28 static void sysrq_sb(struct super_block *sb)
  29 {
  30         char *plevel;
  31         struct au_sbinfo *sbinfo;
  32         struct file *file;
  33         struct au_sphlhead *files;
  34         struct au_finfo *finfo;
  35
  36         plevel = au_plevel;
  37         au_plevel = KERN_WARNING;
  38
  39         /* since we define pr_fmt, call printk directly */
  40 #define pr(str) printk(KERN_WARNING AUFS_NAME ": " str)
  41
  42         sbinfo = au_sbi(sb);
  43         printk(KERN_WARNING "si=%lx\n", sysaufs_si_id(sbinfo));
  44         pr("superblock\n");
  45         au_dpri_sb(sb);
  46
  47 #if 0
  48         pr("root dentry\n");
  49         au_dpri_dentry(sb->s_root);
  50         pr("root inode\n");
  51         au_dpri_inode(d_inode(sb->s_root));
  52 #endif
  53
  54 #if 0
  55         do {
  56                 int err, i, j, ndentry;
  57                 struct au_dcsub_pages dpages;
  58                 struct au_dpage *dpage;
  59
  60                 err = au_dpages_init(&dpages, GFP_ATOMIC);
  61                 if (unlikely(err))
  62                         break;
  63                 err = au_dcsub_pages(&dpages, sb->s_root, NULL, NULL);
  64                 if (!err)
  65                         for (i = 0; i < dpages.ndpage; i++) {
  66                                 dpage = dpages.dpages + i;
  67                                 ndentry = dpage->ndentry;
  68                                 for (j = 0; j < ndentry; j++)
  69                                         au_dpri_dentry(dpage->dentries[j]);
  70                         }
  71                 au_dpages_free(&dpages);
  72         } while (0);
  73 #endif
  74
  75 #if 1
  76         {
  77                 struct inode *i;
  78
  79                 pr("isolated inode\n");
  80                 spin_lock(&sb->s_inode_list_lock);
  81                 list_for_each_entry(i, &sb->s_inodes, i_sb_list) {
  82                         spin_lock(&i->i_lock);
  83                         if (1 || hlist_empty(&i->i_dentry))
  84                                 au_dpri_inode(i);
  85                         spin_unlock(&i->i_lock);
  86                 }
  87                 spin_unlock(&sb->s_inode_list_lock);
  88         }
  89 #endif
  90         pr("files\n");
  91         files = &au_sbi(sb)->si_files;
  92         spin_lock(&files->spin);
  93         hlist_for_each_entry(finfo, &files->head, fi_hlist) {
  94                 umode_t mode;
  95
  96                 file = finfo->fi_file;
  97                 mode = file_inode(file)->i_mode;
  98                 if (!special_file(mode))
  99                         au_dpri_file(file);
 100         }
 101         spin_unlock(&files->spin);
 102         pr("done\n");
 103
 104 #undef pr
 105         au_plevel = plevel;
 106 }
 107
 108 /* ---------------------------------------------------------------------- */
 109
 110 /* module parameter */
 111 static char *aufs_sysrq_key = "a";
 112 module_param_named(sysrq, aufs_sysrq_key, charp, S_IRUGO);
 113 MODULE_PARM_DESC(sysrq, "MagicSysRq key for " AUFS_NAME);
 114
 115 static void au_sysrq(int key __maybe_unused)
 116 {
 117         struct au_sbinfo *sbinfo;
 118
 119         lockdep_off();
 120         au_sbilist_lock();
 121         hlist_for_each_entry(sbinfo, &au_sbilist.head, si_list)
 122                 sysrq_sb(sbinfo->si_sb);
 123         au_sbilist_unlock();
 124         lockdep_on();
 125 }
 126
 127 static struct sysrq_key_op au_sysrq_op = {
 128         .handler        = au_sysrq,
 129         .help_msg       = "Aufs",
 130         .action_msg     = "Aufs",
 131         .enable_mask    = SYSRQ_ENABLE_DUMP
 132 };
 133
 134 /* ---------------------------------------------------------------------- */
 135
 136 int __init au_sysrq_init(void)
 137 {
 138         int err;
 139         char key;
 140
 141         err = -1;
 142         key = *aufs_sysrq_key;
 143         if ('a' <= key && key <= 'z')
 144                 err = register_sysrq_key(key, &au_sysrq_op);
 145         if (unlikely(err))
 146                 pr_err("err %d, sysrq=%c\n", err, key);
 147         return err;
 148 }
 149
 150 void au_sysrq_fin(void)
 151 {
 152         int err;
 153
 154         err = unregister_sysrq_key(*aufs_sysrq_key, &au_sysrq_op);
 155         if (unlikely(err))
 156                 pr_err("err %d (ignored)\n", err);
 157 }