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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 TL |
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 | ||
2174f6df KC |
83 | if (p->psi->erase) |
84 | p->psi->erase(p->type, p->id, p->psi); | |
ca01d6dd TL |
85 | |
86 | return simple_unlink(dir, dentry); | |
87 | } | |
88 | ||
a872d510 TL |
89 | static void pstore_evict_inode(struct inode *inode) |
90 | { | |
6dda9266 TL |
91 | struct pstore_private *p = inode->i_private; |
92 | unsigned long flags; | |
93 | ||
a872d510 | 94 | end_writeback(inode); |
6dda9266 TL |
95 | if (p) { |
96 | spin_lock_irqsave(&allpstore_lock, flags); | |
97 | list_del(&p->list); | |
98 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
99 | kfree(p); | |
100 | } | |
a872d510 TL |
101 | } |
102 | ||
ca01d6dd TL |
103 | static const struct inode_operations pstore_dir_inode_operations = { |
104 | .lookup = simple_lookup, | |
105 | .unlink = pstore_unlink, | |
106 | }; | |
107 | ||
fbe0aa1f TL |
108 | static struct inode *pstore_get_inode(struct super_block *sb, |
109 | const struct inode *dir, int mode, dev_t dev) | |
110 | { | |
111 | struct inode *inode = new_inode(sb); | |
112 | ||
113 | if (inode) { | |
114 | inode->i_ino = get_next_ino(); | |
115 | inode->i_uid = inode->i_gid = 0; | |
116 | inode->i_mode = mode; | |
117 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
118 | switch (mode & S_IFMT) { | |
119 | case S_IFREG: | |
120 | inode->i_fop = &pstore_file_operations; | |
121 | break; | |
122 | case S_IFDIR: | |
123 | inode->i_op = &pstore_dir_inode_operations; | |
124 | inode->i_fop = &simple_dir_operations; | |
125 | inc_nlink(inode); | |
126 | break; | |
127 | } | |
128 | } | |
129 | return inode; | |
130 | } | |
131 | ||
366f7e7a TL |
132 | enum { |
133 | Opt_kmsg_bytes, Opt_err | |
134 | }; | |
135 | ||
136 | static const match_table_t tokens = { | |
137 | {Opt_kmsg_bytes, "kmsg_bytes=%u"}, | |
138 | {Opt_err, NULL} | |
139 | }; | |
140 | ||
141 | static void parse_options(char *options) | |
142 | { | |
143 | char *p; | |
144 | substring_t args[MAX_OPT_ARGS]; | |
145 | int option; | |
146 | ||
147 | if (!options) | |
148 | return; | |
149 | ||
150 | while ((p = strsep(&options, ",")) != NULL) { | |
151 | int token; | |
152 | ||
153 | if (!*p) | |
154 | continue; | |
155 | ||
156 | token = match_token(p, tokens, args); | |
157 | switch (token) { | |
158 | case Opt_kmsg_bytes: | |
159 | if (!match_int(&args[0], &option)) | |
160 | pstore_set_kmsg_bytes(option); | |
161 | break; | |
162 | } | |
163 | } | |
164 | } | |
165 | ||
166 | static int pstore_remount(struct super_block *sb, int *flags, char *data) | |
167 | { | |
168 | parse_options(data); | |
169 | ||
170 | return 0; | |
171 | } | |
172 | ||
ca01d6dd TL |
173 | static const struct super_operations pstore_ops = { |
174 | .statfs = simple_statfs, | |
175 | .drop_inode = generic_delete_inode, | |
a872d510 | 176 | .evict_inode = pstore_evict_inode, |
366f7e7a | 177 | .remount_fs = pstore_remount, |
ca01d6dd TL |
178 | .show_options = generic_show_options, |
179 | }; | |
180 | ||
181 | static struct super_block *pstore_sb; | |
ca01d6dd TL |
182 | |
183 | int pstore_is_mounted(void) | |
184 | { | |
fbe0aa1f | 185 | return pstore_sb != NULL; |
ca01d6dd TL |
186 | } |
187 | ||
188 | /* | |
189 | * Make a regular file in the root directory of our file system. | |
190 | * Load it up with "size" bytes of data from "buf". | |
191 | * Set the mtime & ctime to the date that this record was originally stored. | |
192 | */ | |
193 | int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, | |
638c1fd3 MG |
194 | char *data, size_t size, struct timespec time, |
195 | struct pstore_info *psi) | |
ca01d6dd TL |
196 | { |
197 | struct dentry *root = pstore_sb->s_root; | |
198 | struct dentry *dentry; | |
199 | struct inode *inode; | |
6dda9266 | 200 | int rc = 0; |
ca01d6dd | 201 | char name[PSTORE_NAMELEN]; |
6dda9266 TL |
202 | struct pstore_private *private, *pos; |
203 | unsigned long flags; | |
204 | ||
205 | spin_lock_irqsave(&allpstore_lock, flags); | |
206 | list_for_each_entry(pos, &allpstore, list) { | |
207 | if (pos->type == type && | |
208 | pos->id == id && | |
209 | pos->psi == psi) { | |
210 | rc = -EEXIST; | |
211 | break; | |
212 | } | |
213 | } | |
214 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
215 | if (rc) | |
216 | return rc; | |
ca01d6dd TL |
217 | |
218 | rc = -ENOMEM; | |
219 | inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0); | |
220 | if (!inode) | |
221 | goto fail; | |
fbe0aa1f | 222 | private = kmalloc(sizeof *private + size, GFP_KERNEL); |
ca01d6dd TL |
223 | if (!private) |
224 | goto fail_alloc; | |
56280682 | 225 | private->type = type; |
ca01d6dd | 226 | private->id = id; |
638c1fd3 | 227 | private->psi = psi; |
ca01d6dd TL |
228 | |
229 | switch (type) { | |
230 | case PSTORE_TYPE_DMESG: | |
231 | sprintf(name, "dmesg-%s-%lld", psname, id); | |
232 | break; | |
233 | case PSTORE_TYPE_MCE: | |
234 | sprintf(name, "mce-%s-%lld", psname, id); | |
235 | break; | |
236 | case PSTORE_TYPE_UNKNOWN: | |
237 | sprintf(name, "unknown-%s-%lld", psname, id); | |
238 | break; | |
239 | default: | |
240 | sprintf(name, "type%d-%s-%lld", type, psname, id); | |
241 | break; | |
242 | } | |
243 | ||
244 | mutex_lock(&root->d_inode->i_mutex); | |
245 | ||
246 | rc = -ENOSPC; | |
247 | dentry = d_alloc_name(root, name); | |
248 | if (IS_ERR(dentry)) | |
249 | goto fail_lockedalloc; | |
250 | ||
fbe0aa1f TL |
251 | memcpy(private->data, data, size); |
252 | inode->i_size = private->size = size; | |
ca01d6dd TL |
253 | |
254 | inode->i_private = private; | |
255 | ||
256 | if (time.tv_sec) | |
257 | inode->i_mtime = inode->i_ctime = time; | |
258 | ||
fbe0aa1f | 259 | d_add(dentry, inode); |
ca01d6dd | 260 | |
6dda9266 TL |
261 | spin_lock_irqsave(&allpstore_lock, flags); |
262 | list_add(&private->list, &allpstore); | |
263 | spin_unlock_irqrestore(&allpstore_lock, flags); | |
264 | ||
ca01d6dd | 265 | mutex_unlock(&root->d_inode->i_mutex); |
fbe0aa1f TL |
266 | |
267 | return 0; | |
ca01d6dd TL |
268 | |
269 | fail_lockedalloc: | |
270 | mutex_unlock(&root->d_inode->i_mutex); | |
271 | kfree(private); | |
272 | fail_alloc: | |
273 | iput(inode); | |
274 | ||
275 | fail: | |
276 | return rc; | |
277 | } | |
278 | ||
279 | int pstore_fill_super(struct super_block *sb, void *data, int silent) | |
280 | { | |
318ceed0 | 281 | struct inode *inode; |
ca01d6dd TL |
282 | |
283 | save_mount_options(sb, data); | |
284 | ||
285 | pstore_sb = sb; | |
286 | ||
287 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
288 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
289 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
290 | sb->s_magic = PSTOREFS_MAGIC; | |
291 | sb->s_op = &pstore_ops; | |
292 | sb->s_time_gran = 1; | |
293 | ||
366f7e7a TL |
294 | parse_options(data); |
295 | ||
ca01d6dd | 296 | inode = pstore_get_inode(sb, NULL, S_IFDIR | 0755, 0); |
318ceed0 AV |
297 | if (inode) { |
298 | /* override ramfs "dir" options so we catch unlink(2) */ | |
299 | inode->i_op = &pstore_dir_inode_operations; | |
ca01d6dd | 300 | } |
318ceed0 AV |
301 | sb->s_root = d_make_root(inode); |
302 | if (!sb->s_root) | |
303 | return -ENOMEM; | |
ca01d6dd | 304 | |
6dda9266 | 305 | pstore_get_records(0); |
ca01d6dd TL |
306 | |
307 | return 0; | |
ca01d6dd TL |
308 | } |
309 | ||
fbe0aa1f TL |
310 | static struct dentry *pstore_mount(struct file_system_type *fs_type, |
311 | int flags, const char *dev_name, void *data) | |
ca01d6dd | 312 | { |
fbe0aa1f | 313 | return mount_single(fs_type, flags, data, pstore_fill_super); |
ca01d6dd TL |
314 | } |
315 | ||
316 | static void pstore_kill_sb(struct super_block *sb) | |
317 | { | |
318 | kill_litter_super(sb); | |
319 | pstore_sb = NULL; | |
ca01d6dd TL |
320 | } |
321 | ||
322 | static struct file_system_type pstore_fs_type = { | |
323 | .name = "pstore", | |
fbe0aa1f | 324 | .mount = pstore_mount, |
ca01d6dd TL |
325 | .kill_sb = pstore_kill_sb, |
326 | }; | |
327 | ||
328 | static int __init init_pstore_fs(void) | |
329 | { | |
366f7e7a | 330 | return register_filesystem(&pstore_fs_type); |
ca01d6dd TL |
331 | } |
332 | module_init(init_pstore_fs) | |
333 | ||
334 | MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>"); | |
335 | MODULE_LICENSE("GPL"); |