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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/list.h>
28#include <linux/string.h>
29#include <linux/mount.h>
30#include <linux/ramfs.h>
31#include <linux/parser.h>
32#include <linux/sched.h>
33#include <linux/magic.h>
34#include <linux/pstore.h>
35#include <linux/slab.h>
36#include <linux/spinlock.h>
37#include <linux/uaccess.h>
38
39#include "internal.h"
40
41#define PSTORE_NAMELEN 64
42
43static DEFINE_SPINLOCK(allpstore_lock);
44static LIST_HEAD(allpstore);
45
46struct pstore_private {
47 struct list_head list;
48 struct pstore_info *psi;
49 enum pstore_type_id type;
50 u64 id;
51 ssize_t size;
52 char data[];
53};
54
55static 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
63static const struct file_operations pstore_file_operations = {
64 .open = simple_open,
65 .read = pstore_file_read,
66 .llseek = default_llseek,
67};
68
69
70
71
72
73static int pstore_unlink(struct inode *dir, struct dentry *dentry)
74{
75 struct pstore_private *p = dentry->d_inode->i_private;
76
77 if (p->psi->erase)
78 p->psi->erase(p->type, p->id, p->psi);
79
80 return simple_unlink(dir, dentry);
81}
82
83static void pstore_evict_inode(struct inode *inode)
84{
85 struct pstore_private *p = inode->i_private;
86 unsigned long flags;
87
88 clear_inode(inode);
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 }
95}
96
97static const struct inode_operations pstore_dir_inode_operations = {
98 .lookup = simple_lookup,
99 .unlink = pstore_unlink,
100};
101
102static struct inode *pstore_get_inode(struct super_block *sb)
103{
104 struct inode *inode = new_inode(sb);
105 if (inode) {
106 inode->i_ino = get_next_ino();
107 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
108 }
109 return inode;
110}
111
112enum {
113 Opt_kmsg_bytes, Opt_err
114};
115
116static const match_table_t tokens = {
117 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
118 {Opt_err, NULL}
119};
120
121static 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
146static int pstore_remount(struct super_block *sb, int *flags, char *data)
147{
148 parse_options(data);
149
150 return 0;
151}
152
153static const struct super_operations pstore_ops = {
154 .statfs = simple_statfs,
155 .drop_inode = generic_delete_inode,
156 .evict_inode = pstore_evict_inode,
157 .remount_fs = pstore_remount,
158 .show_options = generic_show_options,
159};
160
161static struct super_block *pstore_sb;
162
163int pstore_is_mounted(void)
164{
165 return pstore_sb != NULL;
166}
167
168
169
170
171
172
173int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
174 char *data, size_t size, struct timespec time,
175 struct pstore_info *psi)
176{
177 struct dentry *root = pstore_sb->s_root;
178 struct dentry *dentry;
179 struct inode *inode;
180 int rc = 0;
181 char name[PSTORE_NAMELEN];
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;
197
198 rc = -ENOMEM;
199 inode = pstore_get_inode(pstore_sb);
200 if (!inode)
201 goto fail;
202 inode->i_mode = S_IFREG | 0444;
203 inode->i_fop = &pstore_file_operations;
204 private = kmalloc(sizeof *private + size, GFP_KERNEL);
205 if (!private)
206 goto fail_alloc;
207 private->type = type;
208 private->id = id;
209 private->psi = psi;
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
233 memcpy(private->data, data, size);
234 inode->i_size = private->size = size;
235
236 inode->i_private = private;
237
238 if (time.tv_sec)
239 inode->i_mtime = inode->i_ctime = time;
240
241 d_add(dentry, inode);
242
243 spin_lock_irqsave(&allpstore_lock, flags);
244 list_add(&private->list, &allpstore);
245 spin_unlock_irqrestore(&allpstore_lock, flags);
246
247 mutex_unlock(&root->d_inode->i_mutex);
248
249 return 0;
250
251fail_lockedalloc:
252 mutex_unlock(&root->d_inode->i_mutex);
253 kfree(private);
254fail_alloc:
255 iput(inode);
256
257fail:
258 return rc;
259}
260
261static int pstore_fill_super(struct super_block *sb, void *data, int silent)
262{
263 struct inode *inode;
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
276 parse_options(data);
277
278 inode = pstore_get_inode(sb);
279 if (inode) {
280 inode->i_mode = S_IFDIR | 0755;
281 inode->i_op = &pstore_dir_inode_operations;
282 inode->i_fop = &simple_dir_operations;
283 inc_nlink(inode);
284 }
285 sb->s_root = d_make_root(inode);
286 if (!sb->s_root)
287 return -ENOMEM;
288
289 pstore_get_records(0);
290
291 return 0;
292}
293
294static struct dentry *pstore_mount(struct file_system_type *fs_type,
295 int flags, const char *dev_name, void *data)
296{
297 return mount_single(fs_type, flags, data, pstore_fill_super);
298}
299
300static void pstore_kill_sb(struct super_block *sb)
301{
302 kill_litter_super(sb);
303 pstore_sb = NULL;
304}
305
306static struct file_system_type pstore_fs_type = {
307 .name = "pstore",
308 .mount = pstore_mount,
309 .kill_sb = pstore_kill_sb,
310};
311
312static int __init init_pstore_fs(void)
313{
314 return register_filesystem(&pstore_fs_type);
315}
316module_init(init_pstore_fs)
317
318MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
319MODULE_LICENSE("GPL");
320
