Commit | Line | Data |
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ca01d6dd TL |
1 | /* |
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> | |
6dda9266 | 27 | #include <linux/list.h> |
ca01d6dd TL |
28 | #include <linux/string.h> |
29 | #include <linux/mount.h> | |
30 | #include <linux/ramfs.h> | |
366f7e7a | 31 | #include <linux/parser.h> |
ca01d6dd TL |
32 | #include <linux/sched.h> |
33 | #include <linux/magic.h> | |
34 | #include <linux/pstore.h> | |
35 | #include <linux/slab.h> | |
6dda9266 | 36 | #include <linux/spinlock.h> |
ca01d6dd TL |
37 | #include <linux/uaccess.h> |
38 | ||
39 | #include "internal.h" | |
40 | ||
41 | #define PSTORE_NAMELEN 64 | |
42 | ||
6dda9266 LT |
43 | static DEFINE_SPINLOCK(allpstore_lock); |
44 | static LIST_HEAD(allpstore); | |
45 | ||
ca01d6dd | 46 | struct pstore_private { |
6dda9266 | 47 | struct list_head list; |
638c1fd3 | 48 | struct pstore_info *psi; |
56280682 MG |
49 | enum pstore_type_id type; |
50 | u64 id; | |
fbe0aa1f TL |
51 | ssize_t size; |
52 | char data[]; | |
ca01d6dd TL |
53 | }; |
54 | ||
fbe0aa1f TL |
55 | static 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 | ||
63 | static const struct file_operations pstore_file_operations = { | |
234e3405 | 64 | .open = simple_open, |
fbe0aa1f TL |
65 | .read = pstore_file_read, |
66 | .llseek = default_llseek, | |
67 | }; | |
ca01d6dd TL |
68 | |
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 | */ | |
73 | static int pstore_unlink(struct inode *dir, struct dentry *dentry) | |
74 | { | |
75 | struct pstore_private *p = dentry->d_inode->i_private; | |
76 | ||
2174f6df KC |
77 | if (p->psi->erase) |
78 | p->psi->erase(p->type, p->id, p->psi); | |
ca01d6dd TL |
79 | |
80 | return simple_unlink(dir, dentry); | |
81 | } | |
82 | ||
a872d510 TL |
83 | static void pstore_evict_inode(struct inode *inode) |
84 | { | |
6dda9266 LT |
85 | struct pstore_private *p = inode->i_private; |
86 | unsigned long flags; | |
87 | ||
dbd5768f | 88 | clear_inode(inode); |
6dda9266 LT |
89 | if (p) { |
90 | spin_lock_irqsave(&allpstore_lock, flags); | |
91 | list_del(&p->list); | |
92 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
93 | kfree(p); | |
94 | } | |
a872d510 TL |
95 | } |
96 | ||
ca01d6dd TL |
97 | static const struct inode_operations pstore_dir_inode_operations = { |
98 | .lookup = simple_lookup, | |
99 | .unlink = pstore_unlink, | |
100 | }; | |
101 | ||
22a71c30 | 102 | static struct inode *pstore_get_inode(struct super_block *sb) |
fbe0aa1f TL |
103 | { |
104 | struct inode *inode = new_inode(sb); | |
fbe0aa1f TL |
105 | if (inode) { |
106 | inode->i_ino = get_next_ino(); | |
fbe0aa1f | 107 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
fbe0aa1f TL |
108 | } |
109 | return inode; | |
110 | } | |
111 | ||
366f7e7a LT |
112 | enum { |
113 | Opt_kmsg_bytes, Opt_err | |
114 | }; | |
115 | ||
116 | static const match_table_t tokens = { | |
117 | {Opt_kmsg_bytes, "kmsg_bytes=%u"}, | |
118 | {Opt_err, NULL} | |
119 | }; | |
120 | ||
121 | static void parse_options(char *options) | |
122 | { | |
123 | char *p; | |
124 | substring_t args[MAX_OPT_ARGS]; | |
125 | int option; | |
126 | ||
127 | if (!options) | |
128 | return; | |
129 | ||
130 | while ((p = strsep(&options, ",")) != NULL) { | |
131 | int token; | |
132 | ||
133 | if (!*p) | |
134 | continue; | |
135 | ||
136 | token = match_token(p, tokens, args); | |
137 | switch (token) { | |
138 | case Opt_kmsg_bytes: | |
139 | if (!match_int(&args[0], &option)) | |
140 | pstore_set_kmsg_bytes(option); | |
141 | break; | |
142 | } | |
143 | } | |
144 | } | |
145 | ||
146 | static int pstore_remount(struct super_block *sb, int *flags, char *data) | |
147 | { | |
148 | parse_options(data); | |
149 | ||
150 | return 0; | |
151 | } | |
152 | ||
ca01d6dd TL |
153 | static const struct super_operations pstore_ops = { |
154 | .statfs = simple_statfs, | |
155 | .drop_inode = generic_delete_inode, | |
a872d510 | 156 | .evict_inode = pstore_evict_inode, |
366f7e7a | 157 | .remount_fs = pstore_remount, |
ca01d6dd TL |
158 | .show_options = generic_show_options, |
159 | }; | |
160 | ||
161 | static struct super_block *pstore_sb; | |
ca01d6dd TL |
162 | |
163 | int pstore_is_mounted(void) | |
164 | { | |
fbe0aa1f | 165 | return pstore_sb != NULL; |
ca01d6dd TL |
166 | } |
167 | ||
168 | /* | |
169 | * Make a regular file in the root directory of our file system. | |
170 | * Load it up with "size" bytes of data from "buf". | |
171 | * Set the mtime & ctime to the date that this record was originally stored. | |
172 | */ | |
173 | int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, | |
638c1fd3 MG |
174 | char *data, size_t size, struct timespec time, |
175 | struct pstore_info *psi) | |
ca01d6dd TL |
176 | { |
177 | struct dentry *root = pstore_sb->s_root; | |
178 | struct dentry *dentry; | |
179 | struct inode *inode; | |
6dda9266 | 180 | int rc = 0; |
ca01d6dd | 181 | char name[PSTORE_NAMELEN]; |
6dda9266 LT |
182 | struct pstore_private *private, *pos; |
183 | unsigned long flags; | |
184 | ||
185 | spin_lock_irqsave(&allpstore_lock, flags); | |
186 | list_for_each_entry(pos, &allpstore, list) { | |
187 | if (pos->type == type && | |
188 | pos->id == id && | |
189 | pos->psi == psi) { | |
190 | rc = -EEXIST; | |
191 | break; | |
192 | } | |
193 | } | |
194 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
195 | if (rc) | |
196 | return rc; | |
ca01d6dd TL |
197 | |
198 | rc = -ENOMEM; | |
22a71c30 | 199 | inode = pstore_get_inode(pstore_sb); |
ca01d6dd TL |
200 | if (!inode) |
201 | goto fail; | |
22a71c30 AV |
202 | inode->i_mode = S_IFREG | 0444; |
203 | inode->i_fop = &pstore_file_operations; | |
fbe0aa1f | 204 | private = kmalloc(sizeof *private + size, GFP_KERNEL); |
ca01d6dd TL |
205 | if (!private) |
206 | goto fail_alloc; | |
56280682 | 207 | private->type = type; |
ca01d6dd | 208 | private->id = id; |
638c1fd3 | 209 | private->psi = psi; |
ca01d6dd TL |
210 | |
211 | switch (type) { | |
212 | case PSTORE_TYPE_DMESG: | |
213 | sprintf(name, "dmesg-%s-%lld", psname, id); | |
214 | break; | |
215 | case PSTORE_TYPE_MCE: | |
216 | sprintf(name, "mce-%s-%lld", psname, id); | |
217 | break; | |
218 | case PSTORE_TYPE_UNKNOWN: | |
219 | sprintf(name, "unknown-%s-%lld", psname, id); | |
220 | break; | |
221 | default: | |
222 | sprintf(name, "type%d-%s-%lld", type, psname, id); | |
223 | break; | |
224 | } | |
225 | ||
226 | mutex_lock(&root->d_inode->i_mutex); | |
227 | ||
228 | rc = -ENOSPC; | |
229 | dentry = d_alloc_name(root, name); | |
230 | if (IS_ERR(dentry)) | |
231 | goto fail_lockedalloc; | |
232 | ||
fbe0aa1f TL |
233 | memcpy(private->data, data, size); |
234 | inode->i_size = private->size = size; | |
ca01d6dd TL |
235 | |
236 | inode->i_private = private; | |
237 | ||
238 | if (time.tv_sec) | |
239 | inode->i_mtime = inode->i_ctime = time; | |
240 | ||
fbe0aa1f | 241 | d_add(dentry, inode); |
ca01d6dd | 242 | |
6dda9266 LT |
243 | spin_lock_irqsave(&allpstore_lock, flags); |
244 | list_add(&private->list, &allpstore); | |
245 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
246 | ||
ca01d6dd | 247 | mutex_unlock(&root->d_inode->i_mutex); |
fbe0aa1f TL |
248 | |
249 | return 0; | |
ca01d6dd TL |
250 | |
251 | fail_lockedalloc: | |
252 | mutex_unlock(&root->d_inode->i_mutex); | |
253 | kfree(private); | |
254 | fail_alloc: | |
255 | iput(inode); | |
256 | ||
257 | fail: | |
258 | return rc; | |
259 | } | |
260 | ||
364ed2f4 | 261 | static int pstore_fill_super(struct super_block *sb, void *data, int silent) |
ca01d6dd | 262 | { |
318ceed0 | 263 | struct inode *inode; |
ca01d6dd TL |
264 | |
265 | save_mount_options(sb, data); | |
266 | ||
267 | pstore_sb = sb; | |
268 | ||
269 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
270 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
271 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
272 | sb->s_magic = PSTOREFS_MAGIC; | |
273 | sb->s_op = &pstore_ops; | |
274 | sb->s_time_gran = 1; | |
275 | ||
366f7e7a LT |
276 | parse_options(data); |
277 | ||
22a71c30 | 278 | inode = pstore_get_inode(sb); |
318ceed0 | 279 | if (inode) { |
22a71c30 | 280 | inode->i_mode = S_IFDIR | 0755; |
318ceed0 | 281 | inode->i_op = &pstore_dir_inode_operations; |
22a71c30 AV |
282 | inode->i_fop = &simple_dir_operations; |
283 | inc_nlink(inode); | |
ca01d6dd | 284 | } |
318ceed0 AV |
285 | sb->s_root = d_make_root(inode); |
286 | if (!sb->s_root) | |
287 | return -ENOMEM; | |
ca01d6dd | 288 | |
6dda9266 | 289 | pstore_get_records(0); |
ca01d6dd TL |
290 | |
291 | return 0; | |
ca01d6dd TL |
292 | } |
293 | ||
fbe0aa1f TL |
294 | static struct dentry *pstore_mount(struct file_system_type *fs_type, |
295 | int flags, const char *dev_name, void *data) | |
ca01d6dd | 296 | { |
fbe0aa1f | 297 | return mount_single(fs_type, flags, data, pstore_fill_super); |
ca01d6dd TL |
298 | } |
299 | ||
300 | static void pstore_kill_sb(struct super_block *sb) | |
301 | { | |
302 | kill_litter_super(sb); | |
303 | pstore_sb = NULL; | |
ca01d6dd TL |
304 | } |
305 | ||
306 | static struct file_system_type pstore_fs_type = { | |
307 | .name = "pstore", | |
fbe0aa1f | 308 | .mount = pstore_mount, |
ca01d6dd TL |
309 | .kill_sb = pstore_kill_sb, |
310 | }; | |
311 | ||
312 | static int __init init_pstore_fs(void) | |
313 | { | |
366f7e7a | 314 | return register_filesystem(&pstore_fs_type); |
ca01d6dd TL |
315 | } |
316 | module_init(init_pstore_fs) | |
317 | ||
318 | MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>"); | |
319 | MODULE_LICENSE("GPL"); |