?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
kthread: fix boot hang (regression) on MIPS/OpenRISC
[linux/fpc-iii.git] / fs / pstore / inode.c
blob792a4e5f9226d16fefa0b6fd47061a76c79416ba
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 #include <linux/syslog.h>
40
41 #include "internal.h"
42
43 #define PSTORE_NAMELEN 64
44
45 static DEFINE_SPINLOCK(allpstore_lock);
46 static LIST_HEAD(allpstore);
47
48 struct pstore_private {
49 struct list_head list;
50 struct pstore_record *record;
51 size_t total_size;
52 };
53
54 struct pstore_ftrace_seq_data {
55 const void *ptr;
56 size_t off;
57 size_t size;
58 };
59
60 #define REC_SIZE sizeof(struct pstore_ftrace_record)
61
62 static void free_pstore_private(struct pstore_private *private)
63 {
64 if (!private)
65 return;
66 if (private->record) {
67 kfree(private->record->buf);
68 kfree(private->record);
69 }
70 kfree(private);
71 }
72
73 static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
74 {
75 struct pstore_private *ps = s->private;
76 struct pstore_ftrace_seq_data *data;
77
78 data = kzalloc(sizeof(*data), GFP_KERNEL);
79 if (!data)
80 return NULL;
81
82 data->off = ps->total_size % REC_SIZE;
83 data->off += *pos * REC_SIZE;
84 if (data->off + REC_SIZE > ps->total_size) {
85 kfree(data);
86 return NULL;
87 }
88
89 return data;
90
91 }
92
93 static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
94 {
95 kfree(v);
96 }
97
98 static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
99 {
100 struct pstore_private *ps = s->private;
101 struct pstore_ftrace_seq_data *data = v;
102
103 data->off += REC_SIZE;
104 if (data->off + REC_SIZE > ps->total_size)
105 return NULL;
106
107 (*pos)++;
108 return data;
109 }
110
111 static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
112 {
113 struct pstore_private *ps = s->private;
114 struct pstore_ftrace_seq_data *data = v;
115 struct pstore_ftrace_record *rec;
116
117 rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
118
119 seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %pf <- %pF\n",
120 pstore_ftrace_decode_cpu(rec),
121 pstore_ftrace_read_timestamp(rec),
122 rec->ip, rec->parent_ip, (void *)rec->ip,
123 (void *)rec->parent_ip);
124
125 return 0;
126 }
127
128 static const struct seq_operations pstore_ftrace_seq_ops = {
129 .start = pstore_ftrace_seq_start,
130 .next = pstore_ftrace_seq_next,
131 .stop = pstore_ftrace_seq_stop,
132 .show = pstore_ftrace_seq_show,
133 };
134
135 static int pstore_check_syslog_permissions(struct pstore_private *ps)
136 {
137 switch (ps->record->type) {
138 case PSTORE_TYPE_DMESG:
139 case PSTORE_TYPE_CONSOLE:
140 return check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
141 SYSLOG_FROM_READER);
142 default:
143 return 0;
144 }
145 }
146
147 static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
148 size_t count, loff_t *ppos)
149 {
150 struct seq_file *sf = file->private_data;
151 struct pstore_private *ps = sf->private;
152
153 if (ps->record->type == PSTORE_TYPE_FTRACE)
154 return seq_read(file, userbuf, count, ppos);
155 return simple_read_from_buffer(userbuf, count, ppos,
156 ps->record->buf, ps->total_size);
157 }
158
159 static int pstore_file_open(struct inode *inode, struct file *file)
160 {
161 struct pstore_private *ps = inode->i_private;
162 struct seq_file *sf;
163 int err;
164 const struct seq_operations *sops = NULL;
165
166 err = pstore_check_syslog_permissions(ps);
167 if (err)
168 return err;
169
170 if (ps->record->type == PSTORE_TYPE_FTRACE)
171 sops = &pstore_ftrace_seq_ops;
172
173 err = seq_open(file, sops);
174 if (err < 0)
175 return err;
176
177 sf = file->private_data;
178 sf->private = ps;
179
180 return 0;
181 }
182
183 static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
184 {
185 struct seq_file *sf = file->private_data;
186
187 if (sf->op)
188 return seq_lseek(file, off, whence);
189 return default_llseek(file, off, whence);
190 }
191
192 static const struct file_operations pstore_file_operations = {
193 .open = pstore_file_open,
194 .read = pstore_file_read,
195 .llseek = pstore_file_llseek,
196 .release = seq_release,
197 };
198
199 /*
200 * When a file is unlinked from our file system we call the
201 * platform driver to erase the record from persistent store.
202 */
203 static int pstore_unlink(struct inode *dir, struct dentry *dentry)
204 {
205 struct pstore_private *p = d_inode(dentry)->i_private;
206 struct pstore_record *record = p->record;
207 int err;
208
209 err = pstore_check_syslog_permissions(p);
210 if (err)
211 return err;
212
213 if (!record->psi->erase)
214 return -EPERM;
215
216 mutex_lock(&record->psi->read_mutex);
217 record->psi->erase(record);
218 mutex_unlock(&record->psi->read_mutex);
219
220 return simple_unlink(dir, dentry);
221 }
222
223 static void pstore_evict_inode(struct inode *inode)
224 {
225 struct pstore_private *p = inode->i_private;
226 unsigned long flags;
227
228 clear_inode(inode);
229 if (p) {
230 spin_lock_irqsave(&allpstore_lock, flags);
231 list_del(&p->list);
232 spin_unlock_irqrestore(&allpstore_lock, flags);
233 free_pstore_private(p);
234 }
235 }
236
237 static const struct inode_operations pstore_dir_inode_operations = {
238 .lookup = simple_lookup,
239 .unlink = pstore_unlink,
240 };
241
242 static struct inode *pstore_get_inode(struct super_block *sb)
243 {
244 struct inode *inode = new_inode(sb);
245 if (inode) {
246 inode->i_ino = get_next_ino();
247 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
248 }
249 return inode;
250 }
251
252 enum {
253 Opt_kmsg_bytes, Opt_err
254 };
255
256 static const match_table_t tokens = {
257 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
258 {Opt_err, NULL}
259 };
260
261 static void parse_options(char *options)
262 {
263 char *p;
264 substring_t args[MAX_OPT_ARGS];
265 int option;
266
267 if (!options)
268 return;
269
270 while ((p = strsep(&options, ",")) != NULL) {
271 int token;
272
273 if (!*p)
274 continue;
275
276 token = match_token(p, tokens, args);
277 switch (token) {
278 case Opt_kmsg_bytes:
279 if (!match_int(&args[0], &option))
280 pstore_set_kmsg_bytes(option);
281 break;
282 }
283 }
284 }
285
286 static int pstore_remount(struct super_block *sb, int *flags, char *data)
287 {
288 sync_filesystem(sb);
289 parse_options(data);
290
291 return 0;
292 }
293
294 static const struct super_operations pstore_ops = {
295 .statfs = simple_statfs,
296 .drop_inode = generic_delete_inode,
297 .evict_inode = pstore_evict_inode,
298 .remount_fs = pstore_remount,
299 .show_options = generic_show_options,
300 };
301
302 static struct super_block *pstore_sb;
303
304 bool pstore_is_mounted(void)
305 {
306 return pstore_sb != NULL;
307 }
308
309 /*
310 * Make a regular file in the root directory of our file system.
311 * Load it up with "size" bytes of data from "buf".
312 * Set the mtime & ctime to the date that this record was originally stored.
313 */
314 int pstore_mkfile(struct dentry *root, struct pstore_record *record)
315 {
316 struct dentry *dentry;
317 struct inode *inode;
318 int rc = 0;
319 char name[PSTORE_NAMELEN];
320 struct pstore_private *private, *pos;
321 unsigned long flags;
322 size_t size = record->size + record->ecc_notice_size;
323
324 WARN_ON(!inode_is_locked(d_inode(root)));
325
326 spin_lock_irqsave(&allpstore_lock, flags);
327 list_for_each_entry(pos, &allpstore, list) {
328 if (pos->record->type == record->type &&
329 pos->record->id == record->id &&
330 pos->record->psi == record->psi) {
331 rc = -EEXIST;
332 break;
333 }
334 }
335 spin_unlock_irqrestore(&allpstore_lock, flags);
336 if (rc)
337 return rc;
338
339 rc = -ENOMEM;
340 inode = pstore_get_inode(root->d_sb);
341 if (!inode)
342 goto fail;
343 inode->i_mode = S_IFREG | 0444;
344 inode->i_fop = &pstore_file_operations;
345 private = kzalloc(sizeof(*private), GFP_KERNEL);
346 if (!private)
347 goto fail_alloc;
348 private->record = record;
349
350 switch (record->type) {
351 case PSTORE_TYPE_DMESG:
352 scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
353 record->psi->name, record->id,
354 record->compressed ? ".enc.z" : "");
355 break;
356 case PSTORE_TYPE_CONSOLE:
357 scnprintf(name, sizeof(name), "console-%s-%lld",
358 record->psi->name, record->id);
359 break;
360 case PSTORE_TYPE_FTRACE:
361 scnprintf(name, sizeof(name), "ftrace-%s-%lld",
362 record->psi->name, record->id);
363 break;
364 case PSTORE_TYPE_MCE:
365 scnprintf(name, sizeof(name), "mce-%s-%lld",
366 record->psi->name, record->id);
367 break;
368 case PSTORE_TYPE_PPC_RTAS:
369 scnprintf(name, sizeof(name), "rtas-%s-%lld",
370 record->psi->name, record->id);
371 break;
372 case PSTORE_TYPE_PPC_OF:
373 scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
374 record->psi->name, record->id);
375 break;
376 case PSTORE_TYPE_PPC_COMMON:
377 scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
378 record->psi->name, record->id);
379 break;
380 case PSTORE_TYPE_PMSG:
381 scnprintf(name, sizeof(name), "pmsg-%s-%lld",
382 record->psi->name, record->id);
383 break;
384 case PSTORE_TYPE_PPC_OPAL:
385 scnprintf(name, sizeof(name), "powerpc-opal-%s-%lld",
386 record->psi->name, record->id);
387 break;
388 case PSTORE_TYPE_UNKNOWN:
389 scnprintf(name, sizeof(name), "unknown-%s-%lld",
390 record->psi->name, record->id);
391 break;
392 default:
393 scnprintf(name, sizeof(name), "type%d-%s-%lld",
394 record->type, record->psi->name, record->id);
395 break;
396 }
397
398 dentry = d_alloc_name(root, name);
399 if (!dentry)
400 goto fail_private;
401
402 inode->i_size = private->total_size = size;
403
404 inode->i_private = private;
405
406 if (record->time.tv_sec)
407 inode->i_mtime = inode->i_ctime = record->time;
408
409 d_add(dentry, inode);
410
411 spin_lock_irqsave(&allpstore_lock, flags);
412 list_add(&private->list, &allpstore);
413 spin_unlock_irqrestore(&allpstore_lock, flags);
414
415 return 0;
416
417 fail_private:
418 free_pstore_private(private);
419 fail_alloc:
420 iput(inode);
421
422 fail:
423 return rc;
424 }
425
426 /*
427 * Read all the records from the persistent store. Create
428 * files in our filesystem. Don't warn about -EEXIST errors
429 * when we are re-scanning the backing store looking to add new
430 * error records.
431 */
432 void pstore_get_records(int quiet)
433 {
434 struct pstore_info *psi = psinfo;
435 struct dentry *root;
436
437 if (!psi || !pstore_sb)
438 return;
439
440 root = pstore_sb->s_root;
441
442 inode_lock(d_inode(root));
443 pstore_get_backend_records(psi, root, quiet);
444 inode_unlock(d_inode(root));
445 }
446
447 static int pstore_fill_super(struct super_block *sb, void *data, int silent)
448 {
449 struct inode *inode;
450
451 save_mount_options(sb, data);
452
453 pstore_sb = sb;
454
455 sb->s_maxbytes = MAX_LFS_FILESIZE;
456 sb->s_blocksize = PAGE_SIZE;
457 sb->s_blocksize_bits = PAGE_SHIFT;
458 sb->s_magic = PSTOREFS_MAGIC;
459 sb->s_op = &pstore_ops;
460 sb->s_time_gran = 1;
461
462 parse_options(data);
463
464 inode = pstore_get_inode(sb);
465 if (inode) {
466 inode->i_mode = S_IFDIR | 0755;
467 inode->i_op = &pstore_dir_inode_operations;
468 inode->i_fop = &simple_dir_operations;
469 inc_nlink(inode);
470 }
471 sb->s_root = d_make_root(inode);
472 if (!sb->s_root)
473 return -ENOMEM;
474
475 pstore_get_records(0);
476
477 return 0;
478 }
479
480 static struct dentry *pstore_mount(struct file_system_type *fs_type,
481 int flags, const char *dev_name, void *data)
482 {
483 return mount_single(fs_type, flags, data, pstore_fill_super);
484 }
485
486 static void pstore_kill_sb(struct super_block *sb)
487 {
488 kill_litter_super(sb);
489 pstore_sb = NULL;
490 }
491
492 static struct file_system_type pstore_fs_type = {
493 .owner = THIS_MODULE,
494 .name = "pstore",
495 .mount = pstore_mount,
496 .kill_sb = pstore_kill_sb,
497 };
498
499 static int __init init_pstore_fs(void)
500 {
501 int err;
502
503 /* Create a convenient mount point for people to access pstore */
504 err = sysfs_create_mount_point(fs_kobj, "pstore");
505 if (err)
506 goto out;
507
508 err = register_filesystem(&pstore_fs_type);
509 if (err < 0)
510 sysfs_remove_mount_point(fs_kobj, "pstore");
511
512 out:
513 return err;
514 }
515 module_init(init_pstore_fs)
516
517 static void __exit exit_pstore_fs(void)
518 {
519 unregister_filesystem(&pstore_fs_type);
520 sysfs_remove_mount_point(fs_kobj, "pstore");
521 }
522 module_exit(exit_pstore_fs)
523
524 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
525 MODULE_LICENSE("GPL");
Linux with added FPC-III support