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 ssize_t btrfs_feature_attr_show(struct kobject *kobj,
  32                                        struct kobj_attribute *a, char *buf)
  33 {
  34         return snprintf(buf, PAGE_SIZE, "0\n");
  35 }
  36
  37 BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
  38 BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
  39 BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
  40 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
  41 BTRFS_FEAT_ATTR_INCOMPAT(compress_lzov2, COMPRESS_LZOv2);
  42 BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
  43 BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
  44 BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
  45 BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
  46
  47 static struct attribute *btrfs_supported_feature_attrs[] = {
  48         BTRFS_FEAT_ATTR_PTR(mixed_backref),
  49         BTRFS_FEAT_ATTR_PTR(default_subvol),
  50         BTRFS_FEAT_ATTR_PTR(mixed_groups),
  51         BTRFS_FEAT_ATTR_PTR(compress_lzo),
  52         BTRFS_FEAT_ATTR_PTR(compress_lzov2),
  53         BTRFS_FEAT_ATTR_PTR(big_metadata),
  54         BTRFS_FEAT_ATTR_PTR(extended_iref),
  55         BTRFS_FEAT_ATTR_PTR(raid56),
  56         BTRFS_FEAT_ATTR_PTR(skinny_metadata),
  57         NULL
  58 };
  59
  60 static const struct attribute_group btrfs_feature_attr_group = {
  61         .name = "features",
  62         .attrs = btrfs_supported_feature_attrs,
  63 };
  64
  65 /* /sys/fs/btrfs/ entry */
  66 static struct kset *btrfs_kset;
  67
  68 int btrfs_init_sysfs(void)
  69 {
  70         int ret;
  71         btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
  72         if (!btrfs_kset)
  73                 return -ENOMEM;
  74
  75         ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
  76         if (ret) {
  77                 kset_unregister(btrfs_kset);
  78                 return ret;
  79         }
  80
  81         return 0;
  82 }
  83
  84 void btrfs_exit_sysfs(void)
  85 {
  86         sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
  87         kset_unregister(btrfs_kset);
  88 }
  89