Root/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/module.h>
25#include <linux/kobject.h>
26
27#include "ctree.h"
28#include "disk-io.h"
29#include "transaction.h"
30
31static ssize_t root_blocks_used_show(struct btrfs_root *root, char *buf)
32{
33    return snprintf(buf, PAGE_SIZE, "%llu\n",
34        (unsigned long long)btrfs_root_used(&root->root_item));
35}
36
37static ssize_t root_block_limit_show(struct btrfs_root *root, char *buf)
38{
39    return snprintf(buf, PAGE_SIZE, "%llu\n",
40        (unsigned long long)btrfs_root_limit(&root->root_item));
41}
42
43static ssize_t super_blocks_used_show(struct btrfs_fs_info *fs, char *buf)
44{
45
46    return snprintf(buf, PAGE_SIZE, "%llu\n",
47        (unsigned long long)btrfs_super_bytes_used(&fs->super_copy));
48}
49
50static ssize_t super_total_blocks_show(struct btrfs_fs_info *fs, char *buf)
51{
52    return snprintf(buf, PAGE_SIZE, "%llu\n",
53        (unsigned long long)btrfs_super_total_bytes(&fs->super_copy));
54}
55
56static ssize_t super_blocksize_show(struct btrfs_fs_info *fs, char *buf)
57{
58    return snprintf(buf, PAGE_SIZE, "%llu\n",
59        (unsigned long long)btrfs_super_sectorsize(&fs->super_copy));
60}
61
62/* this is for root attrs (subvols/snapshots) */
63struct btrfs_root_attr {
64    struct attribute attr;
65    ssize_t (*show)(struct btrfs_root *, char *);
66    ssize_t (*store)(struct btrfs_root *, const char *, size_t);
67};
68
69#define ROOT_ATTR(name, mode, show, store) \
70static struct btrfs_root_attr btrfs_root_attr_##name = __ATTR(name, mode, \
71                                  show, store)
72
73ROOT_ATTR(blocks_used, 0444, root_blocks_used_show, NULL);
74ROOT_ATTR(block_limit, 0644, root_block_limit_show, NULL);
75
76static struct attribute *btrfs_root_attrs[] = {
77    &btrfs_root_attr_blocks_used.attr,
78    &btrfs_root_attr_block_limit.attr,
79    NULL,
80};
81
82/* this is for super attrs (actual full fs) */
83struct btrfs_super_attr {
84    struct attribute attr;
85    ssize_t (*show)(struct btrfs_fs_info *, char *);
86    ssize_t (*store)(struct btrfs_fs_info *, const char *, size_t);
87};
88
89#define SUPER_ATTR(name, mode, show, store) \
90static struct btrfs_super_attr btrfs_super_attr_##name = __ATTR(name, mode, \
91                                show, store)
92
93SUPER_ATTR(blocks_used, 0444, super_blocks_used_show, NULL);
94SUPER_ATTR(total_blocks, 0444, super_total_blocks_show, NULL);
95SUPER_ATTR(blocksize, 0444, super_blocksize_show, NULL);
96
97static struct attribute *btrfs_super_attrs[] = {
98    &btrfs_super_attr_blocks_used.attr,
99    &btrfs_super_attr_total_blocks.attr,
100    &btrfs_super_attr_blocksize.attr,
101    NULL,
102};
103
104static ssize_t btrfs_super_attr_show(struct kobject *kobj,
105                    struct attribute *attr, char *buf)
106{
107    struct btrfs_fs_info *fs = container_of(kobj, struct btrfs_fs_info,
108                        super_kobj);
109    struct btrfs_super_attr *a = container_of(attr,
110                          struct btrfs_super_attr,
111                          attr);
112
113    return a->show ? a->show(fs, buf) : 0;
114}
115
116static ssize_t btrfs_super_attr_store(struct kobject *kobj,
117                     struct attribute *attr,
118                     const char *buf, size_t len)
119{
120    struct btrfs_fs_info *fs = container_of(kobj, struct btrfs_fs_info,
121                        super_kobj);
122    struct btrfs_super_attr *a = container_of(attr,
123                          struct btrfs_super_attr,
124                          attr);
125
126    return a->store ? a->store(fs, buf, len) : 0;
127}
128
129static ssize_t btrfs_root_attr_show(struct kobject *kobj,
130                    struct attribute *attr, char *buf)
131{
132    struct btrfs_root *root = container_of(kobj, struct btrfs_root,
133                        root_kobj);
134    struct btrfs_root_attr *a = container_of(attr,
135                         struct btrfs_root_attr,
136                         attr);
137
138    return a->show ? a->show(root, buf) : 0;
139}
140
141static ssize_t btrfs_root_attr_store(struct kobject *kobj,
142                     struct attribute *attr,
143                     const char *buf, size_t len)
144{
145    struct btrfs_root *root = container_of(kobj, struct btrfs_root,
146                        root_kobj);
147    struct btrfs_root_attr *a = container_of(attr,
148                         struct btrfs_root_attr,
149                         attr);
150    return a->store ? a->store(root, buf, len) : 0;
151}
152
153static void btrfs_super_release(struct kobject *kobj)
154{
155    struct btrfs_fs_info *fs = container_of(kobj, struct btrfs_fs_info,
156                        super_kobj);
157    complete(&fs->kobj_unregister);
158}
159
160static void btrfs_root_release(struct kobject *kobj)
161{
162    struct btrfs_root *root = container_of(kobj, struct btrfs_root,
163                        root_kobj);
164    complete(&root->kobj_unregister);
165}
166
167static const struct sysfs_ops btrfs_super_attr_ops = {
168    .show = btrfs_super_attr_show,
169    .store = btrfs_super_attr_store,
170};
171
172static const struct sysfs_ops btrfs_root_attr_ops = {
173    .show = btrfs_root_attr_show,
174    .store = btrfs_root_attr_store,
175};
176
177static struct kobj_type btrfs_root_ktype = {
178    .default_attrs = btrfs_root_attrs,
179    .sysfs_ops = &btrfs_root_attr_ops,
180    .release = btrfs_root_release,
181};
182
183static struct kobj_type btrfs_super_ktype = {
184    .default_attrs = btrfs_super_attrs,
185    .sysfs_ops = &btrfs_super_attr_ops,
186    .release = btrfs_super_release,
187};
188
189/* /sys/fs/btrfs/ entry */
190static struct kset *btrfs_kset;
191
192int btrfs_sysfs_add_super(struct btrfs_fs_info *fs)
193{
194    int error;
195    char *name;
196    char c;
197    int len = strlen(fs->sb->s_id) + 1;
198    int i;
199
200    name = kmalloc(len, GFP_NOFS);
201    if (!name) {
202        error = -ENOMEM;
203        goto fail;
204    }
205
206    for (i = 0; i < len; i++) {
207        c = fs->sb->s_id[i];
208        if (c == '/' || c == '\\')
209            c = '!';
210        name[i] = c;
211    }
212    name[len] = '\0';
213
214    fs->super_kobj.kset = btrfs_kset;
215    error = kobject_init_and_add(&fs->super_kobj, &btrfs_super_ktype,
216                     NULL, "%s", name);
217    kfree(name);
218    if (error)
219        goto fail;
220
221    return 0;
222
223fail:
224    printk(KERN_ERR "btrfs: sysfs creation for super failed\n");
225    return error;
226}
227
228int btrfs_sysfs_add_root(struct btrfs_root *root)
229{
230    int error;
231
232    error = kobject_init_and_add(&root->root_kobj, &btrfs_root_ktype,
233                     &root->fs_info->super_kobj,
234                     "%s", root->name);
235    if (error)
236        goto fail;
237
238    return 0;
239
240fail:
241    printk(KERN_ERR "btrfs: sysfs creation for root failed\n");
242    return error;
243}
244
245void btrfs_sysfs_del_root(struct btrfs_root *root)
246{
247    kobject_put(&root->root_kobj);
248    wait_for_completion(&root->kobj_unregister);
249}
250
251void btrfs_sysfs_del_super(struct btrfs_fs_info *fs)
252{
253    kobject_put(&fs->super_kobj);
254    wait_for_completion(&fs->kobj_unregister);
255}
256
257int btrfs_init_sysfs(void)
258{
259    btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
260    if (!btrfs_kset)
261        return -ENOMEM;
262    return 0;
263}
264
265void btrfs_exit_sysfs(void)
266{
267    kset_unregister(btrfs_kset);
268}
269
270

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