fs/btrfs/sysfs.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/completion.h>
  23 #include <linux/buffer_head.h>
  24 #include <linux/kobject.h>
  25
  26 #include "ctree.h"
  27 #include "disk-io.h"
  28 #include "transaction.h"
  29 #include "sysfs.h"
  30
  31 static void btrfs_release_super_kobj(struct kobject *kobj);
  32 static struct kobj_type btrfs_ktype = {
  33         .sysfs_ops      = &kobj_sysfs_ops,
  34         .release        = btrfs_release_super_kobj,
  35 };
  36
  37 static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
  38 {
  39         if (kobj->ktype != &btrfs_ktype)
  40                 return NULL;
  41         return container_of(kobj, struct btrfs_fs_info, super_kobj);
  42 }
  43
  44 static void btrfs_release_super_kobj(struct kobject *kobj)
  45 {
  46         struct btrfs_fs_info *fs_info = to_fs_info(kobj);
  47         complete(&fs_info->kobj_unregister);
  48 }
  49
  50 static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
  51                                        struct kobj_attribute *a, char *buf)
  52 {
  53         return snprintf(buf, PAGE_SIZE, "0\n");
  54 }
  55
  56 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
  57 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
  58 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
  59 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
  60 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzov2, COMPRESS_LZOv2);
  61 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
  62 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
  63 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
  64 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
  65
  66 static struct attribute *btrfs_supported_feature_attrs[] = {
  67         BTRFS_FEAT_ATTR_PTR(mixed_backref),
  68         BTRFS_FEAT_ATTR_PTR(default_subvol),
  69         BTRFS_FEAT_ATTR_PTR(mixed_groups),
  70         BTRFS_FEAT_ATTR_PTR(compress_lzo),
  71         BTRFS_FEAT_ATTR_PTR(compress_lzov2),
  72         BTRFS_FEAT_ATTR_PTR(big_metadata),
  73         BTRFS_FEAT_ATTR_PTR(extended_iref),
  74         BTRFS_FEAT_ATTR_PTR(raid56),
  75         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
  76         NULL
  77 };
  78
  79 static const struct attribute_group btrfs_feature_attr_group = {
  80         .name = "features",
  81         .attrs = btrfs_supported_feature_attrs,
  82 };
  83
  84 /* /sys/fs/btrfs/ entry */
  85 static struct kset *btrfs_kset;
  86
  87 void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
  88 {
  89         kobject_del(&fs_info->super_kobj);
  90         kobject_put(&fs_info->super_kobj);
  91         wait_for_completion(&fs_info->kobj_unregister);
  92 }
  93
  94 int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
  95 {
  96         int error;
  97
  98         init_completion(&fs_info->kobj_unregister);
  99         error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
 100                                      "%pU", fs_info->fsid);
 101         return error;
 102 }
 103
 104 int btrfs_init_sysfs(void)
 105 {
 106         int ret;
 107         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
 108         if (!btrfs_kset)
 109                 return -ENOMEM;
 110
 111         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 112         if (ret) {
 113                 kset_unregister(btrfs_kset);
 114                 return ret;
 115         }
 116
 117         return 0;
 118 }
 119
 120 void btrfs_exit_sysfs(void)
 121 {
 122         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
 123         kset_unregister(btrfs_kset);
 124 }
 125