Commit | Line | Data |
---|---|---|
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 int pstore_file_open(struct inode *inode, struct file *file) |
56 | { | |
57 | file->private_data = inode->i_private; | |
58 | return 0; | |
59 | } | |
60 | ||
61 | static ssize_t pstore_file_read(struct file *file, char __user *userbuf, | |
62 | size_t count, loff_t *ppos) | |
63 | { | |
64 | struct pstore_private *ps = file->private_data; | |
65 | ||
66 | return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size); | |
67 | } | |
68 | ||
69 | static const struct file_operations pstore_file_operations = { | |
70 | .open = pstore_file_open, | |
71 | .read = pstore_file_read, | |
72 | .llseek = default_llseek, | |
73 | }; | |
ca01d6dd TL |
74 | |
75 | /* | |
76 | * When a file is unlinked from our file system we call the | |
77 | * platform driver to erase the record from persistent store. | |
78 | */ | |
79 | static int pstore_unlink(struct inode *dir, struct dentry *dentry) | |
80 | { | |
81 | struct pstore_private *p = dentry->d_inode->i_private; | |
82 | ||
56280682 | 83 | p->psi->erase(p->type, p->id, p->psi); |
ca01d6dd TL |
84 | |
85 | return simple_unlink(dir, dentry); | |
86 | } | |
87 | ||
a872d510 TL |
88 | static void pstore_evict_inode(struct inode *inode) |
89 | { | |
6dda9266 LT |
90 | struct pstore_private *p = inode->i_private; |
91 | unsigned long flags; | |
92 | ||
a872d510 | 93 | end_writeback(inode); |
6dda9266 LT |
94 | if (p) { |
95 | spin_lock_irqsave(&allpstore_lock, flags); | |
96 | list_del(&p->list); | |
97 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
98 | kfree(p); | |
99 | } | |
a872d510 TL |
100 | } |
101 | ||
ca01d6dd TL |
102 | static const struct inode_operations pstore_dir_inode_operations = { |
103 | .lookup = simple_lookup, | |
104 | .unlink = pstore_unlink, | |
105 | }; | |
106 | ||
fbe0aa1f TL |
107 | static struct inode *pstore_get_inode(struct super_block *sb, |
108 | const struct inode *dir, int mode, dev_t dev) | |
109 | { | |
110 | struct inode *inode = new_inode(sb); | |
111 | ||
112 | if (inode) { | |
113 | inode->i_ino = get_next_ino(); | |
114 | inode->i_uid = inode->i_gid = 0; | |
115 | inode->i_mode = mode; | |
116 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
117 | switch (mode & S_IFMT) { | |
118 | case S_IFREG: | |
119 | inode->i_fop = &pstore_file_operations; | |
120 | break; | |
121 | case S_IFDIR: | |
122 | inode->i_op = &pstore_dir_inode_operations; | |
123 | inode->i_fop = &simple_dir_operations; | |
124 | inc_nlink(inode); | |
125 | break; | |
126 | } | |
127 | } | |
128 | return inode; | |
129 | } | |
130 | ||
366f7e7a LT |
131 | enum { |
132 | Opt_kmsg_bytes, Opt_err | |
133 | }; | |
134 | ||
135 | static const match_table_t tokens = { | |
136 | {Opt_kmsg_bytes, "kmsg_bytes=%u"}, | |
137 | {Opt_err, NULL} | |
138 | }; | |
139 | ||
140 | static void parse_options(char *options) | |
141 | { | |
142 | char *p; | |
143 | substring_t args[MAX_OPT_ARGS]; | |
144 | int option; | |
145 | ||
146 | if (!options) | |
147 | return; | |
148 | ||
149 | while ((p = strsep(&options, ",")) != NULL) { | |
150 | int token; | |
151 | ||
152 | if (!*p) | |
153 | continue; | |
154 | ||
155 | token = match_token(p, tokens, args); | |
156 | switch (token) { | |
157 | case Opt_kmsg_bytes: | |
158 | if (!match_int(&args[0], &option)) | |
159 | pstore_set_kmsg_bytes(option); | |
160 | break; | |
161 | } | |
162 | } | |
163 | } | |
164 | ||
165 | static int pstore_remount(struct super_block *sb, int *flags, char *data) | |
166 | { | |
167 | parse_options(data); | |
168 | ||
169 | return 0; | |
170 | } | |
171 | ||
ca01d6dd TL |
172 | static const struct super_operations pstore_ops = { |
173 | .statfs = simple_statfs, | |
174 | .drop_inode = generic_delete_inode, | |
a872d510 | 175 | .evict_inode = pstore_evict_inode, |
366f7e7a | 176 | .remount_fs = pstore_remount, |
ca01d6dd TL |
177 | .show_options = generic_show_options, |
178 | }; | |
179 | ||
180 | static struct super_block *pstore_sb; | |
ca01d6dd TL |
181 | |
182 | int pstore_is_mounted(void) | |
183 | { | |
fbe0aa1f | 184 | return pstore_sb != NULL; |
ca01d6dd TL |
185 | } |
186 | ||
187 | /* | |
188 | * Make a regular file in the root directory of our file system. | |
189 | * Load it up with "size" bytes of data from "buf". | |
190 | * Set the mtime & ctime to the date that this record was originally stored. | |
191 | */ | |
192 | int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, | |
638c1fd3 MG |
193 | char *data, size_t size, struct timespec time, |
194 | struct pstore_info *psi) | |
ca01d6dd TL |
195 | { |
196 | struct dentry *root = pstore_sb->s_root; | |
197 | struct dentry *dentry; | |
198 | struct inode *inode; | |
6dda9266 | 199 | int rc = 0; |
ca01d6dd | 200 | char name[PSTORE_NAMELEN]; |
6dda9266 LT |
201 | struct pstore_private *private, *pos; |
202 | unsigned long flags; | |
203 | ||
204 | spin_lock_irqsave(&allpstore_lock, flags); | |
205 | list_for_each_entry(pos, &allpstore, list) { | |
206 | if (pos->type == type && | |
207 | pos->id == id && | |
208 | pos->psi == psi) { | |
209 | rc = -EEXIST; | |
210 | break; | |
211 | } | |
212 | } | |
213 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
214 | if (rc) | |
215 | return rc; | |
ca01d6dd TL |
216 | |
217 | rc = -ENOMEM; | |
218 | inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0); | |
219 | if (!inode) | |
220 | goto fail; | |
fbe0aa1f | 221 | private = kmalloc(sizeof *private + size, GFP_KERNEL); |
ca01d6dd TL |
222 | if (!private) |
223 | goto fail_alloc; | |
56280682 | 224 | private->type = type; |
ca01d6dd | 225 | private->id = id; |
638c1fd3 | 226 | private->psi = psi; |
ca01d6dd TL |
227 | |
228 | switch (type) { | |
229 | case PSTORE_TYPE_DMESG: | |
230 | sprintf(name, "dmesg-%s-%lld", psname, id); | |
231 | break; | |
232 | case PSTORE_TYPE_MCE: | |
233 | sprintf(name, "mce-%s-%lld", psname, id); | |
234 | break; | |
235 | case PSTORE_TYPE_UNKNOWN: | |
236 | sprintf(name, "unknown-%s-%lld", psname, id); | |
237 | break; | |
238 | default: | |
239 | sprintf(name, "type%d-%s-%lld", type, psname, id); | |
240 | break; | |
241 | } | |
242 | ||
243 | mutex_lock(&root->d_inode->i_mutex); | |
244 | ||
245 | rc = -ENOSPC; | |
246 | dentry = d_alloc_name(root, name); | |
247 | if (IS_ERR(dentry)) | |
248 | goto fail_lockedalloc; | |
249 | ||
fbe0aa1f TL |
250 | memcpy(private->data, data, size); |
251 | inode->i_size = private->size = size; | |
ca01d6dd TL |
252 | |
253 | inode->i_private = private; | |
254 | ||
255 | if (time.tv_sec) | |
256 | inode->i_mtime = inode->i_ctime = time; | |
257 | ||
fbe0aa1f | 258 | d_add(dentry, inode); |
ca01d6dd | 259 | |
6dda9266 LT |
260 | spin_lock_irqsave(&allpstore_lock, flags); |
261 | list_add(&private->list, &allpstore); | |
262 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
263 | ||
ca01d6dd | 264 | mutex_unlock(&root->d_inode->i_mutex); |
fbe0aa1f TL |
265 | |
266 | return 0; | |
ca01d6dd TL |
267 | |
268 | fail_lockedalloc: | |
269 | mutex_unlock(&root->d_inode->i_mutex); | |
270 | kfree(private); | |
271 | fail_alloc: | |
272 | iput(inode); | |
273 | ||
274 | fail: | |
275 | return rc; | |
276 | } | |
277 | ||
278 | int pstore_fill_super(struct super_block *sb, void *data, int silent) | |
279 | { | |
280 | struct inode *inode = NULL; | |
281 | struct dentry *root; | |
282 | int err; | |
283 | ||
284 | save_mount_options(sb, data); | |
285 | ||
286 | pstore_sb = sb; | |
287 | ||
288 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
289 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
290 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
291 | sb->s_magic = PSTOREFS_MAGIC; | |
292 | sb->s_op = &pstore_ops; | |
293 | sb->s_time_gran = 1; | |
294 | ||
366f7e7a LT |
295 | parse_options(data); |
296 | ||
ca01d6dd TL |
297 | inode = pstore_get_inode(sb, NULL, S_IFDIR | 0755, 0); |
298 | if (!inode) { | |
299 | err = -ENOMEM; | |
300 | goto fail; | |
301 | } | |
302 | /* override ramfs "dir" options so we catch unlink(2) */ | |
303 | inode->i_op = &pstore_dir_inode_operations; | |
304 | ||
305 | root = d_alloc_root(inode); | |
306 | sb->s_root = root; | |
307 | if (!root) { | |
308 | err = -ENOMEM; | |
309 | goto fail; | |
310 | } | |
311 | ||
6dda9266 | 312 | pstore_get_records(0); |
ca01d6dd TL |
313 | |
314 | return 0; | |
315 | fail: | |
316 | iput(inode); | |
317 | return err; | |
318 | } | |
319 | ||
fbe0aa1f TL |
320 | static struct dentry *pstore_mount(struct file_system_type *fs_type, |
321 | int flags, const char *dev_name, void *data) | |
ca01d6dd | 322 | { |
fbe0aa1f | 323 | return mount_single(fs_type, flags, data, pstore_fill_super); |
ca01d6dd TL |
324 | } |
325 | ||
326 | static void pstore_kill_sb(struct super_block *sb) | |
327 | { | |
328 | kill_litter_super(sb); | |
329 | pstore_sb = NULL; | |
ca01d6dd TL |
330 | } |
331 | ||
332 | static struct file_system_type pstore_fs_type = { | |
333 | .name = "pstore", | |
fbe0aa1f | 334 | .mount = pstore_mount, |
ca01d6dd TL |
335 | .kill_sb = pstore_kill_sb, |
336 | }; | |
337 | ||
338 | static int __init init_pstore_fs(void) | |
339 | { | |
366f7e7a | 340 | return register_filesystem(&pstore_fs_type); |
ca01d6dd TL |
341 | } |
342 | module_init(init_pstore_fs) | |
343 | ||
344 | MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>"); | |
345 | MODULE_LICENSE("GPL"); |