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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 { | |
42 | u64 id; | |
43 | int (*erase)(u64); | |
fbe0aa1f TL |
44 | ssize_t size; |
45 | char data[]; | |
ca01d6dd TL |
46 | }; |
47 | ||
fbe0aa1f TL |
48 | static int pstore_file_open(struct inode *inode, struct file *file) |
49 | { | |
50 | file->private_data = inode->i_private; | |
51 | return 0; | |
52 | } | |
53 | ||
54 | static ssize_t pstore_file_read(struct file *file, char __user *userbuf, | |
55 | size_t count, loff_t *ppos) | |
56 | { | |
57 | struct pstore_private *ps = file->private_data; | |
58 | ||
59 | return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size); | |
60 | } | |
61 | ||
62 | static const struct file_operations pstore_file_operations = { | |
63 | .open = pstore_file_open, | |
64 | .read = pstore_file_read, | |
65 | .llseek = default_llseek, | |
66 | }; | |
ca01d6dd TL |
67 | |
68 | /* | |
69 | * When a file is unlinked from our file system we call the | |
70 | * platform driver to erase the record from persistent store. | |
71 | */ | |
72 | static int pstore_unlink(struct inode *dir, struct dentry *dentry) | |
73 | { | |
74 | struct pstore_private *p = dentry->d_inode->i_private; | |
75 | ||
76 | p->erase(p->id); | |
ca01d6dd TL |
77 | |
78 | return simple_unlink(dir, dentry); | |
79 | } | |
80 | ||
a872d510 TL |
81 | static void pstore_evict_inode(struct inode *inode) |
82 | { | |
83 | end_writeback(inode); | |
84 | kfree(inode->i_private); | |
85 | } | |
86 | ||
ca01d6dd TL |
87 | static const struct inode_operations pstore_dir_inode_operations = { |
88 | .lookup = simple_lookup, | |
89 | .unlink = pstore_unlink, | |
90 | }; | |
91 | ||
fbe0aa1f TL |
92 | static struct inode *pstore_get_inode(struct super_block *sb, |
93 | const struct inode *dir, int mode, dev_t dev) | |
94 | { | |
95 | struct inode *inode = new_inode(sb); | |
96 | ||
97 | if (inode) { | |
98 | inode->i_ino = get_next_ino(); | |
99 | inode->i_uid = inode->i_gid = 0; | |
100 | inode->i_mode = mode; | |
101 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
102 | switch (mode & S_IFMT) { | |
103 | case S_IFREG: | |
104 | inode->i_fop = &pstore_file_operations; | |
105 | break; | |
106 | case S_IFDIR: | |
107 | inode->i_op = &pstore_dir_inode_operations; | |
108 | inode->i_fop = &simple_dir_operations; | |
109 | inc_nlink(inode); | |
110 | break; | |
111 | } | |
112 | } | |
113 | return inode; | |
114 | } | |
115 | ||
366f7e7a TL |
116 | enum { |
117 | Opt_kmsg_bytes, Opt_err | |
118 | }; | |
119 | ||
120 | static const match_table_t tokens = { | |
121 | {Opt_kmsg_bytes, "kmsg_bytes=%u"}, | |
122 | {Opt_err, NULL} | |
123 | }; | |
124 | ||
125 | static void parse_options(char *options) | |
126 | { | |
127 | char *p; | |
128 | substring_t args[MAX_OPT_ARGS]; | |
129 | int option; | |
130 | ||
131 | if (!options) | |
132 | return; | |
133 | ||
134 | while ((p = strsep(&options, ",")) != NULL) { | |
135 | int token; | |
136 | ||
137 | if (!*p) | |
138 | continue; | |
139 | ||
140 | token = match_token(p, tokens, args); | |
141 | switch (token) { | |
142 | case Opt_kmsg_bytes: | |
143 | if (!match_int(&args[0], &option)) | |
144 | pstore_set_kmsg_bytes(option); | |
145 | break; | |
146 | } | |
147 | } | |
148 | } | |
149 | ||
150 | static int pstore_remount(struct super_block *sb, int *flags, char *data) | |
151 | { | |
152 | parse_options(data); | |
153 | ||
154 | return 0; | |
155 | } | |
156 | ||
ca01d6dd TL |
157 | static const struct super_operations pstore_ops = { |
158 | .statfs = simple_statfs, | |
159 | .drop_inode = generic_delete_inode, | |
a872d510 | 160 | .evict_inode = pstore_evict_inode, |
366f7e7a | 161 | .remount_fs = pstore_remount, |
ca01d6dd TL |
162 | .show_options = generic_show_options, |
163 | }; | |
164 | ||
165 | static struct super_block *pstore_sb; | |
ca01d6dd TL |
166 | |
167 | int pstore_is_mounted(void) | |
168 | { | |
fbe0aa1f | 169 | return pstore_sb != NULL; |
ca01d6dd TL |
170 | } |
171 | ||
172 | /* | |
173 | * Make a regular file in the root directory of our file system. | |
174 | * Load it up with "size" bytes of data from "buf". | |
175 | * Set the mtime & ctime to the date that this record was originally stored. | |
176 | */ | |
177 | int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, | |
178 | char *data, size_t size, | |
179 | struct timespec time, int (*erase)(u64)) | |
180 | { | |
181 | struct dentry *root = pstore_sb->s_root; | |
182 | struct dentry *dentry; | |
183 | struct inode *inode; | |
184 | int rc; | |
185 | char name[PSTORE_NAMELEN]; | |
186 | struct pstore_private *private; | |
187 | ||
188 | rc = -ENOMEM; | |
189 | inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0); | |
190 | if (!inode) | |
191 | goto fail; | |
fbe0aa1f | 192 | private = kmalloc(sizeof *private + size, GFP_KERNEL); |
ca01d6dd TL |
193 | if (!private) |
194 | goto fail_alloc; | |
195 | private->id = id; | |
196 | private->erase = erase; | |
197 | ||
198 | switch (type) { | |
199 | case PSTORE_TYPE_DMESG: | |
200 | sprintf(name, "dmesg-%s-%lld", psname, id); | |
201 | break; | |
202 | case PSTORE_TYPE_MCE: | |
203 | sprintf(name, "mce-%s-%lld", psname, id); | |
204 | break; | |
205 | case PSTORE_TYPE_UNKNOWN: | |
206 | sprintf(name, "unknown-%s-%lld", psname, id); | |
207 | break; | |
208 | default: | |
209 | sprintf(name, "type%d-%s-%lld", type, psname, id); | |
210 | break; | |
211 | } | |
212 | ||
213 | mutex_lock(&root->d_inode->i_mutex); | |
214 | ||
215 | rc = -ENOSPC; | |
216 | dentry = d_alloc_name(root, name); | |
217 | if (IS_ERR(dentry)) | |
218 | goto fail_lockedalloc; | |
219 | ||
fbe0aa1f TL |
220 | memcpy(private->data, data, size); |
221 | inode->i_size = private->size = size; | |
ca01d6dd TL |
222 | |
223 | inode->i_private = private; | |
224 | ||
225 | if (time.tv_sec) | |
226 | inode->i_mtime = inode->i_ctime = time; | |
227 | ||
fbe0aa1f | 228 | d_add(dentry, inode); |
ca01d6dd | 229 | |
ca01d6dd | 230 | mutex_unlock(&root->d_inode->i_mutex); |
fbe0aa1f TL |
231 | |
232 | return 0; | |
ca01d6dd TL |
233 | |
234 | fail_lockedalloc: | |
235 | mutex_unlock(&root->d_inode->i_mutex); | |
236 | kfree(private); | |
237 | fail_alloc: | |
238 | iput(inode); | |
239 | ||
240 | fail: | |
241 | return rc; | |
242 | } | |
243 | ||
244 | int pstore_fill_super(struct super_block *sb, void *data, int silent) | |
245 | { | |
246 | struct inode *inode = NULL; | |
247 | struct dentry *root; | |
248 | int err; | |
249 | ||
250 | save_mount_options(sb, data); | |
251 | ||
252 | pstore_sb = sb; | |
253 | ||
254 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
255 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
256 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
257 | sb->s_magic = PSTOREFS_MAGIC; | |
258 | sb->s_op = &pstore_ops; | |
259 | sb->s_time_gran = 1; | |
260 | ||
366f7e7a TL |
261 | parse_options(data); |
262 | ||
ca01d6dd TL |
263 | inode = pstore_get_inode(sb, NULL, S_IFDIR | 0755, 0); |
264 | if (!inode) { | |
265 | err = -ENOMEM; | |
266 | goto fail; | |
267 | } | |
268 | /* override ramfs "dir" options so we catch unlink(2) */ | |
269 | inode->i_op = &pstore_dir_inode_operations; | |
270 | ||
271 | root = d_alloc_root(inode); | |
272 | sb->s_root = root; | |
273 | if (!root) { | |
274 | err = -ENOMEM; | |
275 | goto fail; | |
276 | } | |
277 | ||
278 | pstore_get_records(); | |
279 | ||
280 | return 0; | |
281 | fail: | |
282 | iput(inode); | |
283 | return err; | |
284 | } | |
285 | ||
fbe0aa1f TL |
286 | static struct dentry *pstore_mount(struct file_system_type *fs_type, |
287 | int flags, const char *dev_name, void *data) | |
ca01d6dd | 288 | { |
fbe0aa1f | 289 | return mount_single(fs_type, flags, data, pstore_fill_super); |
ca01d6dd TL |
290 | } |
291 | ||
292 | static void pstore_kill_sb(struct super_block *sb) | |
293 | { | |
294 | kill_litter_super(sb); | |
295 | pstore_sb = NULL; | |
ca01d6dd TL |
296 | } |
297 | ||
298 | static struct file_system_type pstore_fs_type = { | |
299 | .name = "pstore", | |
fbe0aa1f | 300 | .mount = pstore_mount, |
ca01d6dd TL |
301 | .kill_sb = pstore_kill_sb, |
302 | }; | |
303 | ||
304 | static int __init init_pstore_fs(void) | |
305 | { | |
366f7e7a | 306 | return register_filesystem(&pstore_fs_type); |
ca01d6dd TL |
307 | } |
308 | module_init(init_pstore_fs) | |
309 | ||
310 | MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>"); | |
311 | MODULE_LICENSE("GPL"); |