2
* Persistent Storage - ramfs parts.
4
* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
6
* This program is free software; you can redistribute it and/or modify
7
* it under the terms of the GNU General Public License version 2 as
8
* published by the Free Software Foundation.
10
* This program is distributed in the hope that it will be useful,
11
* but WITHOUT ANY WARRANTY; without even the implied warranty of
12
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13
* GNU General Public License for more details.
15
* You should have received a copy of the GNU General Public License
16
* along with this program; if not, write to the Free Software
17
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20
#include <linux/module.h>
22
#include <linux/fsnotify.h>
23
#include <linux/pagemap.h>
24
#include <linux/highmem.h>
25
#include <linux/time.h>
26
#include <linux/init.h>
27
#include <linux/string.h>
28
#include <linux/mount.h>
29
#include <linux/ramfs.h>
30
#include <linux/parser.h>
31
#include <linux/sched.h>
32
#include <linux/magic.h>
33
#include <linux/pstore.h>
34
#include <linux/slab.h>
35
#include <linux/uaccess.h>
39
#define PSTORE_NAMELEN 64
41
struct pstore_private {
48
static int pstore_file_open(struct inode *inode, struct file *file)
50
file->private_data = inode->i_private;
54
static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
55
size_t count, loff_t *ppos)
57
struct pstore_private *ps = file->private_data;
59
return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
62
static const struct file_operations pstore_file_operations = {
63
.open = pstore_file_open,
64
.read = pstore_file_read,
65
.llseek = default_llseek,
69
* When a file is unlinked from our file system we call the
70
* platform driver to erase the record from persistent store.
72
static int pstore_unlink(struct inode *dir, struct dentry *dentry)
74
struct pstore_private *p = dentry->d_inode->i_private;
78
return simple_unlink(dir, dentry);
81
static void pstore_evict_inode(struct inode *inode)
84
kfree(inode->i_private);
87
static const struct inode_operations pstore_dir_inode_operations = {
88
.lookup = simple_lookup,
89
.unlink = pstore_unlink,
92
static struct inode *pstore_get_inode(struct super_block *sb,
93
const struct inode *dir, int mode, dev_t dev)
95
struct inode *inode = new_inode(sb);
98
inode->i_ino = get_next_ino();
99
inode->i_uid = inode->i_gid = 0;
100
inode->i_mode = mode;
101
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
102
switch (mode & S_IFMT) {
104
inode->i_fop = &pstore_file_operations;
107
inode->i_op = &pstore_dir_inode_operations;
108
inode->i_fop = &simple_dir_operations;
117
Opt_kmsg_bytes, Opt_err
120
static const match_table_t tokens = {
121
{Opt_kmsg_bytes, "kmsg_bytes=%u"},
125
static void parse_options(char *options)
128
substring_t args[MAX_OPT_ARGS];
134
while ((p = strsep(&options, ",")) != NULL) {
140
token = match_token(p, tokens, args);
143
if (!match_int(&args[0], &option))
144
pstore_set_kmsg_bytes(option);
150
static int pstore_remount(struct super_block *sb, int *flags, char *data)
157
static const struct super_operations pstore_ops = {
158
.statfs = simple_statfs,
159
.drop_inode = generic_delete_inode,
160
.evict_inode = pstore_evict_inode,
161
.remount_fs = pstore_remount,
162
.show_options = generic_show_options,
165
static struct super_block *pstore_sb;
167
int pstore_is_mounted(void)
169
return pstore_sb != NULL;
173
* Make a regular file in the root directory of our file system.
174
* Load it up with "size" bytes of data from "buf".
175
* Set the mtime & ctime to the date that this record was originally stored.
177
int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
178
char *data, size_t size,
179
struct timespec time, int (*erase)(u64))
181
struct dentry *root = pstore_sb->s_root;
182
struct dentry *dentry;
185
char name[PSTORE_NAMELEN];
186
struct pstore_private *private;
189
inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0);
192
private = kmalloc(sizeof *private + size, GFP_KERNEL);
196
private->erase = erase;
199
case PSTORE_TYPE_DMESG:
200
sprintf(name, "dmesg-%s-%lld", psname, id);
202
case PSTORE_TYPE_MCE:
203
sprintf(name, "mce-%s-%lld", psname, id);
205
case PSTORE_TYPE_UNKNOWN:
206
sprintf(name, "unknown-%s-%lld", psname, id);
209
sprintf(name, "type%d-%s-%lld", type, psname, id);
213
mutex_lock(&root->d_inode->i_mutex);
216
dentry = d_alloc_name(root, name);
218
goto fail_lockedalloc;
220
memcpy(private->data, data, size);
221
inode->i_size = private->size = size;
223
inode->i_private = private;
226
inode->i_mtime = inode->i_ctime = time;
228
d_add(dentry, inode);
230
mutex_unlock(&root->d_inode->i_mutex);
235
mutex_unlock(&root->d_inode->i_mutex);
244
int pstore_fill_super(struct super_block *sb, void *data, int silent)
246
struct inode *inode = NULL;
250
save_mount_options(sb, data);
254
sb->s_maxbytes = MAX_LFS_FILESIZE;
255
sb->s_blocksize = PAGE_CACHE_SIZE;
256
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
257
sb->s_magic = PSTOREFS_MAGIC;
258
sb->s_op = &pstore_ops;
263
inode = pstore_get_inode(sb, NULL, S_IFDIR | 0755, 0);
268
/* override ramfs "dir" options so we catch unlink(2) */
269
inode->i_op = &pstore_dir_inode_operations;
271
root = d_alloc_root(inode);
278
pstore_get_records();
286
static struct dentry *pstore_mount(struct file_system_type *fs_type,
287
int flags, const char *dev_name, void *data)
289
return mount_single(fs_type, flags, data, pstore_fill_super);
292
static void pstore_kill_sb(struct super_block *sb)
294
kill_litter_super(sb);
298
static struct file_system_type pstore_fs_type = {
300
.mount = pstore_mount,
301
.kill_sb = pstore_kill_sb,
304
static int __init init_pstore_fs(void)
306
return register_filesystem(&pstore_fs_type);
308
module_init(init_pstore_fs)
310
MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
311
MODULE_LICENSE("GPL");