fs/nilfs2/sysfs.c

   1 /*
   2  * sysfs.c - sysfs support implementation.
   3  *
   4  * Copyright (C) 2005-2014 Nippon Telegraph and Telephone Corporation.
   5  * Copyright (C) 2014 HGST, Inc., a Western Digital Company.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * Written by Vyacheslav Dubeyko <Vyacheslav.Dubeyko@hgst.com>
  18  */
  19
  20 #include <linux/kobject.h>
  21
  22 #include "nilfs.h"
  23 #include "mdt.h"
  24 #include "sufile.h"
  25 #include "cpfile.h"
  26 #include "sysfs.h"
  27
  28 /* /sys/fs/<nilfs>/ */
  29 static struct kset *nilfs_kset;
  30
  31 #define NILFS_SHOW_TIME(time_t_val, buf) ({ \
  32                 struct tm res; \
  33                 int count = 0; \
  34                 time_to_tm(time_t_val, 0, &res); \
  35                 res.tm_year += 1900; \
  36                 res.tm_mon += 1; \
  37                 count = scnprintf(buf, PAGE_SIZE, \
  38                                     "%ld-%.2d-%.2d %.2d:%.2d:%.2d\n", \
  39                                     res.tm_year, res.tm_mon, res.tm_mday, \
  40                                     res.tm_hour, res.tm_min, res.tm_sec);\
  41                 count; \
  42 })
  43
  44 /************************************************************************
  45  *                        NILFS feature attrs                           *
  46  ************************************************************************/
  47
  48 static ssize_t nilfs_feature_revision_show(struct kobject *kobj,
  49                                             struct attribute *attr, char *buf)
  50 {
  51         return snprintf(buf, PAGE_SIZE, "%d.%d\n",
  52                         NILFS_CURRENT_REV, NILFS_MINOR_REV);
  53 }
  54
  55 static const char features_readme_str[] =
  56         "The features group contains attributes that describe NILFS file\n"
  57         "system driver features.\n\n"
  58         "(1) revision\n\tshow current revision of NILFS file system driver.\n";
  59
  60 static ssize_t nilfs_feature_README_show(struct kobject *kobj,
  61                                          struct attribute *attr,
  62                                          char *buf)
  63 {
  64         return snprintf(buf, PAGE_SIZE, features_readme_str);
  65 }
  66
  67 NILFS_FEATURE_RO_ATTR(revision);
  68 NILFS_FEATURE_RO_ATTR(README);
  69
  70 static struct attribute *nilfs_feature_attrs[] = {
  71         NILFS_FEATURE_ATTR_LIST(revision),
  72         NILFS_FEATURE_ATTR_LIST(README),
  73         NULL,
  74 };
  75
  76 static const struct attribute_group nilfs_feature_attr_group = {
  77         .name = "features",
  78         .attrs = nilfs_feature_attrs,
  79 };
  80
  81 int __init nilfs_sysfs_init(void)
  82 {
  83         int err;
  84
  85         nilfs_kset = kset_create_and_add(NILFS_ROOT_GROUP_NAME, NULL, fs_kobj);
  86         if (!nilfs_kset) {
  87                 err = -ENOMEM;
  88                 printk(KERN_ERR "NILFS: unable to create sysfs entry: err %d\n",
  89                         err);
  90                 goto failed_sysfs_init;
  91         }
  92
  93         err = sysfs_create_group(&nilfs_kset->kobj, &nilfs_feature_attr_group);
  94         if (unlikely(err)) {
  95                 printk(KERN_ERR "NILFS: unable to create feature group: err %d\n",
  96                         err);
  97                 goto cleanup_sysfs_init;
  98         }
  99
 100         return 0;
 101
 102 cleanup_sysfs_init:
 103         kset_unregister(nilfs_kset);
 104
 105 failed_sysfs_init:
 106         return err;
 107 }
 108
 109 void nilfs_sysfs_exit(void)
 110 {
 111         sysfs_remove_group(&nilfs_kset->kobj, &nilfs_feature_attr_group);
 112         kset_unregister(nilfs_kset);
 113 }