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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / fs / pstore / inode.c
blobd814723fb27dcdfc80168bf97a5c10ab20fcc0c2
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/list.h>
28 #include <linux/string.h>
29 #include <linux/mount.h>
30 #include <linux/seq_file.h>
31 #include <linux/ramfs.h>
32 #include <linux/parser.h>
33 #include <linux/sched.h>
34 #include <linux/magic.h>
35 #include <linux/pstore.h>
36 #include <linux/slab.h>
37 #include <linux/spinlock.h>
38 #include <linux/uaccess.h>
39
40 #include "internal.h"
41
42 #define PSTORE_NAMELEN 64
43
44 static DEFINE_SPINLOCK(allpstore_lock);
45 static LIST_HEAD(allpstore);
46
47 struct pstore_private {
48 struct list_head list;
49 struct pstore_record *record;
50 size_t total_size;
51 };
52
53 struct pstore_ftrace_seq_data {
54 const void *ptr;
55 size_t off;
56 size_t size;
57 };
58
59 #define REC_SIZE sizeof(struct pstore_ftrace_record)
60
61 static void free_pstore_private(struct pstore_private *private)
62 {
63 if (!private)
64 return;
65 if (private->record) {
66 kfree(private->record->buf);
67 kfree(private->record);
68 }
69 kfree(private);
70 }
71
72 static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
73 {
74 struct pstore_private *ps = s->private;
75 struct pstore_ftrace_seq_data *data;
76
77 data = kzalloc(sizeof(*data), GFP_KERNEL);
78 if (!data)
79 return NULL;
80
81 data->off = ps->total_size % REC_SIZE;
82 data->off += *pos * REC_SIZE;
83 if (data->off + REC_SIZE > ps->total_size) {
84 kfree(data);
85 return NULL;
86 }
87
88 return data;
89
90 }
91
92 static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
93 {
94 kfree(v);
95 }
96
97 static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
98 {
99 struct pstore_private *ps = s->private;
100 struct pstore_ftrace_seq_data *data = v;
101
102 data->off += REC_SIZE;
103 if (data->off + REC_SIZE > ps->total_size)
104 return NULL;
105
106 (*pos)++;
107 return data;
108 }
109
110 static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
111 {
112 struct pstore_private *ps = s->private;
113 struct pstore_ftrace_seq_data *data = v;
114 struct pstore_ftrace_record *rec;
115
116 rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
117
118 seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %pf <- %pF\n",
119 pstore_ftrace_decode_cpu(rec),
120 pstore_ftrace_read_timestamp(rec),
121 rec->ip, rec->parent_ip, (void *)rec->ip,
122 (void *)rec->parent_ip);
123
124 return 0;
125 }
126
127 static const struct seq_operations pstore_ftrace_seq_ops = {
128 .start = pstore_ftrace_seq_start,
129 .next = pstore_ftrace_seq_next,
130 .stop = pstore_ftrace_seq_stop,
131 .show = pstore_ftrace_seq_show,
132 };
133
134 static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
135 size_t count, loff_t *ppos)
136 {
137 struct seq_file *sf = file->private_data;
138 struct pstore_private *ps = sf->private;
139
140 if (ps->record->type == PSTORE_TYPE_FTRACE)
141 return seq_read(file, userbuf, count, ppos);
142 return simple_read_from_buffer(userbuf, count, ppos,
143 ps->record->buf, ps->total_size);
144 }
145
146 static int pstore_file_open(struct inode *inode, struct file *file)
147 {
148 struct pstore_private *ps = inode->i_private;
149 struct seq_file *sf;
150 int err;
151 const struct seq_operations *sops = NULL;
152
153 if (ps->record->type == PSTORE_TYPE_FTRACE)
154 sops = &pstore_ftrace_seq_ops;
155
156 err = seq_open(file, sops);
157 if (err < 0)
158 return err;
159
160 sf = file->private_data;
161 sf->private = ps;
162
163 return 0;
164 }
165
166 static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
167 {
168 struct seq_file *sf = file->private_data;
169
170 if (sf->op)
171 return seq_lseek(file, off, whence);
172 return default_llseek(file, off, whence);
173 }
174
175 static const struct file_operations pstore_file_operations = {
176 .open = pstore_file_open,
177 .read = pstore_file_read,
178 .llseek = pstore_file_llseek,
179 .release = seq_release,
180 };
181
182 /*
183 * When a file is unlinked from our file system we call the
184 * platform driver to erase the record from persistent store.
185 */
186 static int pstore_unlink(struct inode *dir, struct dentry *dentry)
187 {
188 struct pstore_private *p = d_inode(dentry)->i_private;
189 struct pstore_record *record = p->record;
190
191 if (!record->psi->erase)
192 return -EPERM;
193
194 mutex_lock(&record->psi->read_mutex);
195 record->psi->erase(record);
196 mutex_unlock(&record->psi->read_mutex);
197
198 return simple_unlink(dir, dentry);
199 }
200
201 static void pstore_evict_inode(struct inode *inode)
202 {
203 struct pstore_private *p = inode->i_private;
204 unsigned long flags;
205
206 clear_inode(inode);
207 if (p) {
208 spin_lock_irqsave(&allpstore_lock, flags);
209 list_del(&p->list);
210 spin_unlock_irqrestore(&allpstore_lock, flags);
211 free_pstore_private(p);
212 }
213 }
214
215 static const struct inode_operations pstore_dir_inode_operations = {
216 .lookup = simple_lookup,
217 .unlink = pstore_unlink,
218 };
219
220 static struct inode *pstore_get_inode(struct super_block *sb)
221 {
222 struct inode *inode = new_inode(sb);
223 if (inode) {
224 inode->i_ino = get_next_ino();
225 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
226 }
227 return inode;
228 }
229
230 enum {
231 Opt_kmsg_bytes, Opt_err
232 };
233
234 static const match_table_t tokens = {
235 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
236 {Opt_err, NULL}
237 };
238
239 static void parse_options(char *options)
240 {
241 char *p;
242 substring_t args[MAX_OPT_ARGS];
243 int option;
244
245 if (!options)
246 return;
247
248 while ((p = strsep(&options, ",")) != NULL) {
249 int token;
250
251 if (!*p)
252 continue;
253
254 token = match_token(p, tokens, args);
255 switch (token) {
256 case Opt_kmsg_bytes:
257 if (!match_int(&args[0], &option))
258 pstore_set_kmsg_bytes(option);
259 break;
260 }
261 }
262 }
263
264 /*
265 * Display the mount options in /proc/mounts.
266 */
267 static int pstore_show_options(struct seq_file *m, struct dentry *root)
268 {
269 if (kmsg_bytes != PSTORE_DEFAULT_KMSG_BYTES)
270 seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes);
271 return 0;
272 }
273
274 static int pstore_remount(struct super_block *sb, int *flags, char *data)
275 {
276 sync_filesystem(sb);
277 parse_options(data);
278
279 return 0;
280 }
281
282 static const struct super_operations pstore_ops = {
283 .statfs = simple_statfs,
284 .drop_inode = generic_delete_inode,
285 .evict_inode = pstore_evict_inode,
286 .remount_fs = pstore_remount,
287 .show_options = pstore_show_options,
288 };
289
290 static struct super_block *pstore_sb;
291
292 bool pstore_is_mounted(void)
293 {
294 return pstore_sb != NULL;
295 }
296
297 /*
298 * Make a regular file in the root directory of our file system.
299 * Load it up with "size" bytes of data from "buf".
300 * Set the mtime & ctime to the date that this record was originally stored.
301 */
302 int pstore_mkfile(struct dentry *root, struct pstore_record *record)
303 {
304 struct dentry *dentry;
305 struct inode *inode;
306 int rc = 0;
307 char name[PSTORE_NAMELEN];
308 struct pstore_private *private, *pos;
309 unsigned long flags;
310 size_t size = record->size + record->ecc_notice_size;
311
312 WARN_ON(!inode_is_locked(d_inode(root)));
313
314 spin_lock_irqsave(&allpstore_lock, flags);
315 list_for_each_entry(pos, &allpstore, list) {
316 if (pos->record->type == record->type &&
317 pos->record->id == record->id &&
318 pos->record->psi == record->psi) {
319 rc = -EEXIST;
320 break;
321 }
322 }
323 spin_unlock_irqrestore(&allpstore_lock, flags);
324 if (rc)
325 return rc;
326
327 rc = -ENOMEM;
328 inode = pstore_get_inode(root->d_sb);
329 if (!inode)
330 goto fail;
331 inode->i_mode = S_IFREG | 0444;
332 inode->i_fop = &pstore_file_operations;
333 private = kzalloc(sizeof(*private), GFP_KERNEL);
334 if (!private)
335 goto fail_alloc;
336 private->record = record;
337
338 switch (record->type) {
339 case PSTORE_TYPE_DMESG:
340 scnprintf(name, sizeof(name), "dmesg-%s-%llu%s",
341 record->psi->name, record->id,
342 record->compressed ? ".enc.z" : "");
343 break;
344 case PSTORE_TYPE_CONSOLE:
345 scnprintf(name, sizeof(name), "console-%s-%llu",
346 record->psi->name, record->id);
347 break;
348 case PSTORE_TYPE_FTRACE:
349 scnprintf(name, sizeof(name), "ftrace-%s-%llu",
350 record->psi->name, record->id);
351 break;
352 case PSTORE_TYPE_MCE:
353 scnprintf(name, sizeof(name), "mce-%s-%llu",
354 record->psi->name, record->id);
355 break;
356 case PSTORE_TYPE_PPC_RTAS:
357 scnprintf(name, sizeof(name), "rtas-%s-%llu",
358 record->psi->name, record->id);
359 break;
360 case PSTORE_TYPE_PPC_OF:
361 scnprintf(name, sizeof(name), "powerpc-ofw-%s-%llu",
362 record->psi->name, record->id);
363 break;
364 case PSTORE_TYPE_PPC_COMMON:
365 scnprintf(name, sizeof(name), "powerpc-common-%s-%llu",
366 record->psi->name, record->id);
367 break;
368 case PSTORE_TYPE_PMSG:
369 scnprintf(name, sizeof(name), "pmsg-%s-%llu",
370 record->psi->name, record->id);
371 break;
372 case PSTORE_TYPE_PPC_OPAL:
373 scnprintf(name, sizeof(name), "powerpc-opal-%s-%llu",
374 record->psi->name, record->id);
375 break;
376 case PSTORE_TYPE_UNKNOWN:
377 scnprintf(name, sizeof(name), "unknown-%s-%llu",
378 record->psi->name, record->id);
379 break;
380 default:
381 scnprintf(name, sizeof(name), "type%d-%s-%llu",
382 record->type, record->psi->name, record->id);
383 break;
384 }
385
386 dentry = d_alloc_name(root, name);
387 if (!dentry)
388 goto fail_private;
389
390 inode->i_size = private->total_size = size;
391
392 inode->i_private = private;
393
394 if (record->time.tv_sec)
395 inode->i_mtime = inode->i_ctime = record->time;
396
397 d_add(dentry, inode);
398
399 spin_lock_irqsave(&allpstore_lock, flags);
400 list_add(&private->list, &allpstore);
401 spin_unlock_irqrestore(&allpstore_lock, flags);
402
403 return 0;
404
405 fail_private:
406 free_pstore_private(private);
407 fail_alloc:
408 iput(inode);
409
410 fail:
411 return rc;
412 }
413
414 /*
415 * Read all the records from the persistent store. Create
416 * files in our filesystem. Don't warn about -EEXIST errors
417 * when we are re-scanning the backing store looking to add new
418 * error records.
419 */
420 void pstore_get_records(int quiet)
421 {
422 struct pstore_info *psi = psinfo;
423 struct dentry *root;
424
425 if (!psi || !pstore_sb)
426 return;
427
428 root = pstore_sb->s_root;
429
430 inode_lock(d_inode(root));
431 pstore_get_backend_records(psi, root, quiet);
432 inode_unlock(d_inode(root));
433 }
434
435 static int pstore_fill_super(struct super_block *sb, void *data, int silent)
436 {
437 struct inode *inode;
438
439 pstore_sb = sb;
440
441 sb->s_maxbytes = MAX_LFS_FILESIZE;
442 sb->s_blocksize = PAGE_SIZE;
443 sb->s_blocksize_bits = PAGE_SHIFT;
444 sb->s_magic = PSTOREFS_MAGIC;
445 sb->s_op = &pstore_ops;
446 sb->s_time_gran = 1;
447
448 parse_options(data);
449
450 inode = pstore_get_inode(sb);
451 if (inode) {
452 inode->i_mode = S_IFDIR | 0750;
453 inode->i_op = &pstore_dir_inode_operations;
454 inode->i_fop = &simple_dir_operations;
455 inc_nlink(inode);
456 }
457 sb->s_root = d_make_root(inode);
458 if (!sb->s_root)
459 return -ENOMEM;
460
461 pstore_get_records(0);
462
463 return 0;
464 }
465
466 static struct dentry *pstore_mount(struct file_system_type *fs_type,
467 int flags, const char *dev_name, void *data)
468 {
469 return mount_single(fs_type, flags, data, pstore_fill_super);
470 }
471
472 static void pstore_kill_sb(struct super_block *sb)
473 {
474 kill_litter_super(sb);
475 pstore_sb = NULL;
476 }
477
478 static struct file_system_type pstore_fs_type = {
479 .owner = THIS_MODULE,
480 .name = "pstore",
481 .mount = pstore_mount,
482 .kill_sb = pstore_kill_sb,
483 };
484
485 static int __init init_pstore_fs(void)
486 {
487 int err;
488
489 /* Create a convenient mount point for people to access pstore */
490 err = sysfs_create_mount_point(fs_kobj, "pstore");
491 if (err)
492 goto out;
493
494 err = register_filesystem(&pstore_fs_type);
495 if (err < 0)
496 sysfs_remove_mount_point(fs_kobj, "pstore");
497
498 out:
499 return err;
500 }
501 module_init(init_pstore_fs)
502
503 static void __exit exit_pstore_fs(void)
504 {
505 unregister_filesystem(&pstore_fs_type);
506 sysfs_remove_mount_point(fs_kobj, "pstore");
507 }
508 module_exit(exit_pstore_fs)
509
510 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
511 MODULE_LICENSE("GPL");
CRIS linux kernel tree