blob: 893b961dcfd8b45219a9266ca4db78ee9b44fb71 [file] [log] [blame]
Tony Luckca01d6d2010-12-28 14:25:21 -08001/*
2 * Persistent Storage - ramfs parts.
3 *
4 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
5 *
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.
9 *
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.
14 *
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
18 */
19
20#include <linux/module.h>
21#include <linux/fs.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>
Luck, Tony366f7e72011-03-18 15:33:43 -070030#include <linux/parser.h>
Tony Luckca01d6d2010-12-28 14:25:21 -080031#include <linux/sched.h>
32#include <linux/magic.h>
33#include <linux/pstore.h>
34#include <linux/slab.h>
35#include <linux/uaccess.h>
36
37#include "internal.h"
38
39#define PSTORE_NAMELEN 64
40
41struct pstore_private {
Matthew Garrett638c1fd2011-07-21 16:57:52 -040042 struct pstore_info *psi;
Matthew Garrett56280682011-07-21 16:57:53 -040043 enum pstore_type_id type;
44 u64 id;
Tony Luckfbe0aa12011-03-17 16:29:15 -070045 ssize_t size;
46 char data[];
Tony Luckca01d6d2010-12-28 14:25:21 -080047};
48
Tony Luckfbe0aa12011-03-17 16:29:15 -070049static int pstore_file_open(struct inode *inode, struct file *file)
50{
51 file->private_data = inode->i_private;
52 return 0;
53}
54
55static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
56 size_t count, loff_t *ppos)
57{
58 struct pstore_private *ps = file->private_data;
59
60 return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
61}
62
63static const struct file_operations pstore_file_operations = {
64 .open = pstore_file_open,
65 .read = pstore_file_read,
66 .llseek = default_llseek,
67};
Tony Luckca01d6d2010-12-28 14:25:21 -080068
69/*
70 * When a file is unlinked from our file system we call the
71 * platform driver to erase the record from persistent store.
72 */
73static int pstore_unlink(struct inode *dir, struct dentry *dentry)
74{
75 struct pstore_private *p = dentry->d_inode->i_private;
76
Matthew Garrett56280682011-07-21 16:57:53 -040077 p->psi->erase(p->type, p->id, p->psi);
Tony Luckca01d6d2010-12-28 14:25:21 -080078
79 return simple_unlink(dir, dentry);
80}
81
Tony Lucka872d512011-03-18 11:44:48 -070082static void pstore_evict_inode(struct inode *inode)
83{
84 end_writeback(inode);
85 kfree(inode->i_private);
86}
87
Tony Luckca01d6d2010-12-28 14:25:21 -080088static const struct inode_operations pstore_dir_inode_operations = {
89 .lookup = simple_lookup,
90 .unlink = pstore_unlink,
91};
92
Tony Luckfbe0aa12011-03-17 16:29:15 -070093static struct inode *pstore_get_inode(struct super_block *sb,
94 const struct inode *dir, int mode, dev_t dev)
95{
96 struct inode *inode = new_inode(sb);
97
98 if (inode) {
99 inode->i_ino = get_next_ino();
100 inode->i_uid = inode->i_gid = 0;
101 inode->i_mode = mode;
102 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
103 switch (mode & S_IFMT) {
104 case S_IFREG:
105 inode->i_fop = &pstore_file_operations;
106 break;
107 case S_IFDIR:
108 inode->i_op = &pstore_dir_inode_operations;
109 inode->i_fop = &simple_dir_operations;
110 inc_nlink(inode);
111 break;
112 }
113 }
114 return inode;
115}
116
Luck, Tony366f7e72011-03-18 15:33:43 -0700117enum {
118 Opt_kmsg_bytes, Opt_err
119};
120
121static const match_table_t tokens = {
122 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
123 {Opt_err, NULL}
124};
125
126static void parse_options(char *options)
127{
128 char *p;
129 substring_t args[MAX_OPT_ARGS];
130 int option;
131
132 if (!options)
133 return;
134
135 while ((p = strsep(&options, ",")) != NULL) {
136 int token;
137
138 if (!*p)
139 continue;
140
141 token = match_token(p, tokens, args);
142 switch (token) {
143 case Opt_kmsg_bytes:
144 if (!match_int(&args[0], &option))
145 pstore_set_kmsg_bytes(option);
146 break;
147 }
148 }
149}
150
151static int pstore_remount(struct super_block *sb, int *flags, char *data)
152{
153 parse_options(data);
154
155 return 0;
156}
157
Tony Luckca01d6d2010-12-28 14:25:21 -0800158static const struct super_operations pstore_ops = {
159 .statfs = simple_statfs,
160 .drop_inode = generic_delete_inode,
Tony Lucka872d512011-03-18 11:44:48 -0700161 .evict_inode = pstore_evict_inode,
Luck, Tony366f7e72011-03-18 15:33:43 -0700162 .remount_fs = pstore_remount,
Tony Luckca01d6d2010-12-28 14:25:21 -0800163 .show_options = generic_show_options,
164};
165
166static struct super_block *pstore_sb;
Tony Luckca01d6d2010-12-28 14:25:21 -0800167
168int pstore_is_mounted(void)
169{
Tony Luckfbe0aa12011-03-17 16:29:15 -0700170 return pstore_sb != NULL;
Tony Luckca01d6d2010-12-28 14:25:21 -0800171}
172
173/*
174 * Make a regular file in the root directory of our file system.
175 * Load it up with "size" bytes of data from "buf".
176 * Set the mtime & ctime to the date that this record was originally stored.
177 */
178int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
Matthew Garrett638c1fd2011-07-21 16:57:52 -0400179 char *data, size_t size, struct timespec time,
180 struct pstore_info *psi)
Tony Luckca01d6d2010-12-28 14:25:21 -0800181{
182 struct dentry *root = pstore_sb->s_root;
183 struct dentry *dentry;
184 struct inode *inode;
185 int rc;
186 char name[PSTORE_NAMELEN];
187 struct pstore_private *private;
188
189 rc = -ENOMEM;
190 inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0);
191 if (!inode)
192 goto fail;
Tony Luckfbe0aa12011-03-17 16:29:15 -0700193 private = kmalloc(sizeof *private + size, GFP_KERNEL);
Tony Luckca01d6d2010-12-28 14:25:21 -0800194 if (!private)
195 goto fail_alloc;
Matthew Garrett56280682011-07-21 16:57:53 -0400196 private->type = type;
Tony Luckca01d6d2010-12-28 14:25:21 -0800197 private->id = id;
Matthew Garrett638c1fd2011-07-21 16:57:52 -0400198 private->psi = psi;
Tony Luckca01d6d2010-12-28 14:25:21 -0800199
200 switch (type) {
201 case PSTORE_TYPE_DMESG:
202 sprintf(name, "dmesg-%s-%lld", psname, id);
203 break;
204 case PSTORE_TYPE_MCE:
205 sprintf(name, "mce-%s-%lld", psname, id);
206 break;
207 case PSTORE_TYPE_UNKNOWN:
208 sprintf(name, "unknown-%s-%lld", psname, id);
209 break;
210 default:
211 sprintf(name, "type%d-%s-%lld", type, psname, id);
212 break;
213 }
214
215 mutex_lock(&root->d_inode->i_mutex);
216
217 rc = -ENOSPC;
218 dentry = d_alloc_name(root, name);
219 if (IS_ERR(dentry))
220 goto fail_lockedalloc;
221
Tony Luckfbe0aa12011-03-17 16:29:15 -0700222 memcpy(private->data, data, size);
223 inode->i_size = private->size = size;
Tony Luckca01d6d2010-12-28 14:25:21 -0800224
225 inode->i_private = private;
226
227 if (time.tv_sec)
228 inode->i_mtime = inode->i_ctime = time;
229
Tony Luckfbe0aa12011-03-17 16:29:15 -0700230 d_add(dentry, inode);
Tony Luckca01d6d2010-12-28 14:25:21 -0800231
Tony Luckca01d6d2010-12-28 14:25:21 -0800232 mutex_unlock(&root->d_inode->i_mutex);
Tony Luckfbe0aa12011-03-17 16:29:15 -0700233
234 return 0;
Tony Luckca01d6d2010-12-28 14:25:21 -0800235
236fail_lockedalloc:
237 mutex_unlock(&root->d_inode->i_mutex);
238 kfree(private);
239fail_alloc:
240 iput(inode);
241
242fail:
243 return rc;
244}
245
246int pstore_fill_super(struct super_block *sb, void *data, int silent)
247{
248 struct inode *inode = NULL;
249 struct dentry *root;
250 int err;
251
252 save_mount_options(sb, data);
253
254 pstore_sb = sb;
255
256 sb->s_maxbytes = MAX_LFS_FILESIZE;
257 sb->s_blocksize = PAGE_CACHE_SIZE;
258 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
259 sb->s_magic = PSTOREFS_MAGIC;
260 sb->s_op = &pstore_ops;
261 sb->s_time_gran = 1;
262
Luck, Tony366f7e72011-03-18 15:33:43 -0700263 parse_options(data);
264
Tony Luckca01d6d2010-12-28 14:25:21 -0800265 inode = pstore_get_inode(sb, NULL, S_IFDIR | 0755, 0);
266 if (!inode) {
267 err = -ENOMEM;
268 goto fail;
269 }
270 /* override ramfs "dir" options so we catch unlink(2) */
271 inode->i_op = &pstore_dir_inode_operations;
272
273 root = d_alloc_root(inode);
274 sb->s_root = root;
275 if (!root) {
276 err = -ENOMEM;
277 goto fail;
278 }
279
280 pstore_get_records();
281
282 return 0;
283fail:
284 iput(inode);
285 return err;
286}
287
Tony Luckfbe0aa12011-03-17 16:29:15 -0700288static struct dentry *pstore_mount(struct file_system_type *fs_type,
289 int flags, const char *dev_name, void *data)
Tony Luckca01d6d2010-12-28 14:25:21 -0800290{
Tony Luckfbe0aa12011-03-17 16:29:15 -0700291 return mount_single(fs_type, flags, data, pstore_fill_super);
Tony Luckca01d6d2010-12-28 14:25:21 -0800292}
293
294static void pstore_kill_sb(struct super_block *sb)
295{
296 kill_litter_super(sb);
297 pstore_sb = NULL;
Tony Luckca01d6d2010-12-28 14:25:21 -0800298}
299
300static struct file_system_type pstore_fs_type = {
301 .name = "pstore",
Tony Luckfbe0aa12011-03-17 16:29:15 -0700302 .mount = pstore_mount,
Tony Luckca01d6d2010-12-28 14:25:21 -0800303 .kill_sb = pstore_kill_sb,
304};
305
306static int __init init_pstore_fs(void)
307{
Luck, Tony366f7e72011-03-18 15:33:43 -0700308 return register_filesystem(&pstore_fs_type);
Tony Luckca01d6d2010-12-28 14:25:21 -0800309}
310module_init(init_pstore_fs)
311
312MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
313MODULE_LICENSE("GPL");