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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> | |
27 | #include <linux/string.h> | |
28 | #include <linux/mount.h> | |
29 | #include <linux/ramfs.h> | |
366f7e7a | 30 | #include <linux/parser.h> |
ca01d6dd TL |
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> | |
36 | ||
37 | #include "internal.h" | |
38 | ||
39 | #define PSTORE_NAMELEN 64 | |
40 | ||
41 | struct pstore_private { | |
638c1fd3 | 42 | struct pstore_info *psi; |
56280682 MG |
43 | enum pstore_type_id type; |
44 | u64 id; | |
fbe0aa1f TL |
45 | ssize_t size; |
46 | char data[]; | |
ca01d6dd TL |
47 | }; |
48 | ||
fbe0aa1f TL |
49 | static int pstore_file_open(struct inode *inode, struct file *file) |
50 | { | |
51 | file->private_data = inode->i_private; | |
52 | return 0; | |
53 | } | |
54 | ||
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 = { | |
64 | .open = pstore_file_open, | |
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 | ||
56280682 | 77 | p->psi->erase(p->type, p->id, p->psi); |
ca01d6dd TL |
78 | |
79 | return simple_unlink(dir, dentry); | |
80 | } | |
81 | ||
a872d510 TL |
82 | static void pstore_evict_inode(struct inode *inode) |
83 | { | |
84 | end_writeback(inode); | |
85 | kfree(inode->i_private); | |
86 | } | |
87 | ||
ca01d6dd TL |
88 | static const struct inode_operations pstore_dir_inode_operations = { |
89 | .lookup = simple_lookup, | |
90 | .unlink = pstore_unlink, | |
91 | }; | |
92 | ||
fbe0aa1f TL |
93 | static 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 | ||
366f7e7a TL |
117 | enum { |
118 | Opt_kmsg_bytes, Opt_err | |
119 | }; | |
120 | ||
121 | static const match_table_t tokens = { | |
122 | {Opt_kmsg_bytes, "kmsg_bytes=%u"}, | |
123 | {Opt_err, NULL} | |
124 | }; | |
125 | ||
126 | static 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 | ||
151 | static int pstore_remount(struct super_block *sb, int *flags, char *data) | |
152 | { | |
153 | parse_options(data); | |
154 | ||
155 | return 0; | |
156 | } | |
157 | ||
ca01d6dd TL |
158 | static const struct super_operations pstore_ops = { |
159 | .statfs = simple_statfs, | |
160 | .drop_inode = generic_delete_inode, | |
a872d510 | 161 | .evict_inode = pstore_evict_inode, |
366f7e7a | 162 | .remount_fs = pstore_remount, |
ca01d6dd TL |
163 | .show_options = generic_show_options, |
164 | }; | |
165 | ||
166 | static struct super_block *pstore_sb; | |
ca01d6dd TL |
167 | |
168 | int pstore_is_mounted(void) | |
169 | { | |
fbe0aa1f | 170 | return pstore_sb != NULL; |
ca01d6dd TL |
171 | } |
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 | */ | |
178 | int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, | |
638c1fd3 MG |
179 | char *data, size_t size, struct timespec time, |
180 | struct pstore_info *psi) | |
ca01d6dd TL |
181 | { |
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; | |
fbe0aa1f | 193 | private = kmalloc(sizeof *private + size, GFP_KERNEL); |
ca01d6dd TL |
194 | if (!private) |
195 | goto fail_alloc; | |
56280682 | 196 | private->type = type; |
ca01d6dd | 197 | private->id = id; |
638c1fd3 | 198 | private->psi = psi; |
ca01d6dd TL |
199 | |
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 | ||
fbe0aa1f TL |
222 | memcpy(private->data, data, size); |
223 | inode->i_size = private->size = size; | |
ca01d6dd TL |
224 | |
225 | inode->i_private = private; | |
226 | ||
227 | if (time.tv_sec) | |
228 | inode->i_mtime = inode->i_ctime = time; | |
229 | ||
fbe0aa1f | 230 | d_add(dentry, inode); |
ca01d6dd | 231 | |
ca01d6dd | 232 | mutex_unlock(&root->d_inode->i_mutex); |
fbe0aa1f TL |
233 | |
234 | return 0; | |
ca01d6dd TL |
235 | |
236 | fail_lockedalloc: | |
237 | mutex_unlock(&root->d_inode->i_mutex); | |
238 | kfree(private); | |
239 | fail_alloc: | |
240 | iput(inode); | |
241 | ||
242 | fail: | |
243 | return rc; | |
244 | } | |
245 | ||
246 | int 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 | ||
366f7e7a TL |
263 | parse_options(data); |
264 | ||
ca01d6dd TL |
265 | 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; | |
283 | fail: | |
284 | iput(inode); | |
285 | return err; | |
286 | } | |
287 | ||
fbe0aa1f TL |
288 | static struct dentry *pstore_mount(struct file_system_type *fs_type, |
289 | int flags, const char *dev_name, void *data) | |
ca01d6dd | 290 | { |
fbe0aa1f | 291 | return mount_single(fs_type, flags, data, pstore_fill_super); |
ca01d6dd TL |
292 | } |
293 | ||
294 | static void pstore_kill_sb(struct super_block *sb) | |
295 | { | |
296 | kill_litter_super(sb); | |
297 | pstore_sb = NULL; | |
ca01d6dd TL |
298 | } |
299 | ||
300 | static struct file_system_type pstore_fs_type = { | |
301 | .name = "pstore", | |
fbe0aa1f | 302 | .mount = pstore_mount, |
ca01d6dd TL |
303 | .kill_sb = pstore_kill_sb, |
304 | }; | |
305 | ||
306 | static int __init init_pstore_fs(void) | |
307 | { | |
366f7e7a | 308 | return register_filesystem(&pstore_fs_type); |
ca01d6dd TL |
309 | } |
310 | module_init(init_pstore_fs) | |
311 | ||
312 | MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>"); | |
313 | MODULE_LICENSE("GPL"); |