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path: root/fs/pstore/inode.c (plain)
blob: 1781dc50762e2fe03391e8efa8c0ff5577cd7cf6
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
45static DEFINE_SPINLOCK(allpstore_lock);
46static LIST_HEAD(allpstore);
47
48struct pstore_private {
49 struct list_head list;
50 struct pstore_info *psi;
51 enum pstore_type_id type;
52 u64 id;
53 int count;
54 ssize_t size;
55 char data[];
56};
57
58struct pstore_ftrace_seq_data {
59 const void *ptr;
60 size_t off;
61 size_t size;
62};
63
64#define REC_SIZE sizeof(struct pstore_ftrace_record)
65
66static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
67{
68 struct pstore_private *ps = s->private;
69 struct pstore_ftrace_seq_data *data;
70
71 data = kzalloc(sizeof(*data), GFP_KERNEL);
72 if (!data)
73 return NULL;
74
75 data->off = ps->size % REC_SIZE;
76 data->off += *pos * REC_SIZE;
77 if (data->off + REC_SIZE > ps->size) {
78 kfree(data);
79 return NULL;
80 }
81
82 return data;
83
84}
85
86static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
87{
88 kfree(v);
89}
90
91static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
92{
93 struct pstore_private *ps = s->private;
94 struct pstore_ftrace_seq_data *data = v;
95
96 data->off += REC_SIZE;
97 if (data->off + REC_SIZE > ps->size)
98 return NULL;
99
100 (*pos)++;
101 return data;
102}
103
104static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
105{
106 struct pstore_private *ps = s->private;
107 struct pstore_ftrace_seq_data *data = v;
108 struct pstore_ftrace_record *rec = (void *)(ps->data + data->off);
109
110 seq_printf(s, "%d %08lx %08lx %pf <- %pF\n",
111 pstore_ftrace_decode_cpu(rec), rec->ip, rec->parent_ip,
112 (void *)rec->ip, (void *)rec->parent_ip);
113
114 return 0;
115}
116
117static const struct seq_operations pstore_ftrace_seq_ops = {
118 .start = pstore_ftrace_seq_start,
119 .next = pstore_ftrace_seq_next,
120 .stop = pstore_ftrace_seq_stop,
121 .show = pstore_ftrace_seq_show,
122};
123
124static int pstore_check_syslog_permissions(struct pstore_private *ps)
125{
126 switch (ps->type) {
127 case PSTORE_TYPE_DMESG:
128 case PSTORE_TYPE_CONSOLE:
129 return check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
130 SYSLOG_FROM_READER);
131 default:
132 return 0;
133 }
134}
135
136static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
137 size_t count, loff_t *ppos)
138{
139 struct seq_file *sf = file->private_data;
140 struct pstore_private *ps = sf->private;
141
142 if (ps->type == PSTORE_TYPE_FTRACE)
143 return seq_read(file, userbuf, count, ppos);
144 return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
145}
146
147static int pstore_file_open(struct inode *inode, struct file *file)
148{
149 struct pstore_private *ps = inode->i_private;
150 struct seq_file *sf;
151 int err;
152 const struct seq_operations *sops = NULL;
153
154 err = pstore_check_syslog_permissions(ps);
155 if (err)
156 return err;
157
158 if (ps->type == PSTORE_TYPE_FTRACE)
159 sops = &pstore_ftrace_seq_ops;
160
161 err = seq_open(file, sops);
162 if (err < 0)
163 return err;
164
165 sf = file->private_data;
166 sf->private = ps;
167
168 return 0;
169}
170
171static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
172{
173 struct seq_file *sf = file->private_data;
174
175 if (sf->op)
176 return seq_lseek(file, off, whence);
177 return default_llseek(file, off, whence);
178}
179
180static const struct file_operations pstore_file_operations = {
181 .open = pstore_file_open,
182 .read = pstore_file_read,
183 .llseek = pstore_file_llseek,
184 .release = seq_release,
185};
186
187/*
188 * When a file is unlinked from our file system we call the
189 * platform driver to erase the record from persistent store.
190 */
191static int pstore_unlink(struct inode *dir, struct dentry *dentry)
192{
193 struct pstore_private *p = d_inode(dentry)->i_private;
194 int err;
195
196 err = pstore_check_syslog_permissions(p);
197 if (err)
198 return err;
199
200 if (p->psi->erase)
201 p->psi->erase(p->type, p->id, p->count,
202 d_inode(dentry)->i_ctime, p->psi);
203 else
204 return -EPERM;
205
206 return simple_unlink(dir, dentry);
207}
208
209static void pstore_evict_inode(struct inode *inode)
210{
211 struct pstore_private *p = inode->i_private;
212 unsigned long flags;
213
214 clear_inode(inode);
215 if (p) {
216 spin_lock_irqsave(&allpstore_lock, flags);
217 list_del(&p->list);
218 spin_unlock_irqrestore(&allpstore_lock, flags);
219 kfree(p);
220 }
221}
222
223static const struct inode_operations pstore_dir_inode_operations = {
224 .lookup = simple_lookup,
225 .unlink = pstore_unlink,
226};
227
228static struct inode *pstore_get_inode(struct super_block *sb)
229{
230 struct inode *inode = new_inode(sb);
231 if (inode) {
232 inode->i_ino = get_next_ino();
233 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
234 }
235 return inode;
236}
237
238enum {
239 Opt_kmsg_bytes, Opt_err
240};
241
242static const match_table_t tokens = {
243 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
244 {Opt_err, NULL}
245};
246
247static void parse_options(char *options)
248{
249 char *p;
250 substring_t args[MAX_OPT_ARGS];
251 int option;
252
253 if (!options)
254 return;
255
256 while ((p = strsep(&options, ",")) != NULL) {
257 int token;
258
259 if (!*p)
260 continue;
261
262 token = match_token(p, tokens, args);
263 switch (token) {
264 case Opt_kmsg_bytes:
265 if (!match_int(&args[0], &option))
266 pstore_set_kmsg_bytes(option);
267 break;
268 }
269 }
270}
271
272static int pstore_remount(struct super_block *sb, int *flags, char *data)
273{
274 sync_filesystem(sb);
275 parse_options(data);
276
277 return 0;
278}
279
280static const struct super_operations pstore_ops = {
281 .statfs = simple_statfs,
282 .drop_inode = generic_delete_inode,
283 .evict_inode = pstore_evict_inode,
284 .remount_fs = pstore_remount,
285 .show_options = generic_show_options,
286};
287
288static struct super_block *pstore_sb;
289
290bool pstore_is_mounted(void)
291{
292 return pstore_sb != NULL;
293}
294
295/*
296 * Make a regular file in the root directory of our file system.
297 * Load it up with "size" bytes of data from "buf".
298 * Set the mtime & ctime to the date that this record was originally stored.
299 */
300int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
301 char *data, bool compressed, size_t size,
302 struct timespec time, struct pstore_info *psi)
303{
304 struct dentry *root = pstore_sb->s_root;
305 struct dentry *dentry;
306 struct inode *inode;
307 int rc = 0;
308 char name[PSTORE_NAMELEN];
309 struct pstore_private *private, *pos;
310 unsigned long flags;
311
312 spin_lock_irqsave(&allpstore_lock, flags);
313 list_for_each_entry(pos, &allpstore, list) {
314 if (pos->type == type &&
315 pos->id == id &&
316 pos->psi == psi) {
317 rc = -EEXIST;
318 break;
319 }
320 }
321 spin_unlock_irqrestore(&allpstore_lock, flags);
322 if (rc)
323 return rc;
324
325 rc = -ENOMEM;
326 inode = pstore_get_inode(pstore_sb);
327 if (!inode)
328 goto fail;
329 inode->i_mode = S_IFREG | 0444;
330 inode->i_fop = &pstore_file_operations;
331 private = kmalloc(sizeof *private + size, GFP_KERNEL);
332 if (!private)
333 goto fail_alloc;
334 private->type = type;
335 private->id = id;
336 private->count = count;
337 private->psi = psi;
338
339 switch (type) {
340 case PSTORE_TYPE_DMESG:
341 scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
342 psname, id, compressed ? ".enc.z" : "");
343 break;
344 case PSTORE_TYPE_CONSOLE:
345 scnprintf(name, sizeof(name), "console-%s-%lld", psname, id);
346 break;
347 case PSTORE_TYPE_FTRACE:
348 scnprintf(name, sizeof(name), "ftrace-%s-%lld", psname, id);
349 break;
350 case PSTORE_TYPE_MCE:
351 scnprintf(name, sizeof(name), "mce-%s-%lld", psname, id);
352 break;
353 case PSTORE_TYPE_PPC_RTAS:
354 scnprintf(name, sizeof(name), "rtas-%s-%lld", psname, id);
355 break;
356 case PSTORE_TYPE_PPC_OF:
357 scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
358 psname, id);
359 break;
360 case PSTORE_TYPE_PPC_COMMON:
361 scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
362 psname, id);
363 break;
364 case PSTORE_TYPE_PMSG:
365 scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id);
366 break;
367 case PSTORE_TYPE_PPC_OPAL:
368 sprintf(name, "powerpc-opal-%s-%lld", psname, id);
369 break;
370 case PSTORE_TYPE_UNKNOWN:
371 scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id);
372 break;
373 default:
374 scnprintf(name, sizeof(name), "type%d-%s-%lld",
375 type, psname, id);
376 break;
377 }
378
379 inode_lock(d_inode(root));
380
381 dentry = d_alloc_name(root, name);
382 if (!dentry)
383 goto fail_lockedalloc;
384
385 memcpy(private->data, data, size);
386 inode->i_size = private->size = size;
387
388 inode->i_private = private;
389
390 if (time.tv_sec)
391 inode->i_mtime = inode->i_ctime = time;
392
393 d_add(dentry, inode);
394
395 spin_lock_irqsave(&allpstore_lock, flags);
396 list_add(&private->list, &allpstore);
397 spin_unlock_irqrestore(&allpstore_lock, flags);
398
399 inode_unlock(d_inode(root));
400
401 return 0;
402
403fail_lockedalloc:
404 inode_unlock(d_inode(root));
405 kfree(private);
406fail_alloc:
407 iput(inode);
408
409fail:
410 return rc;
411}
412
413static int pstore_fill_super(struct super_block *sb, void *data, int silent)
414{
415 struct inode *inode;
416
417 save_mount_options(sb, data);
418
419 pstore_sb = sb;
420
421 sb->s_maxbytes = MAX_LFS_FILESIZE;
422 sb->s_blocksize = PAGE_SIZE;
423 sb->s_blocksize_bits = PAGE_SHIFT;
424 sb->s_magic = PSTOREFS_MAGIC;
425 sb->s_op = &pstore_ops;
426 sb->s_time_gran = 1;
427
428 parse_options(data);
429
430 inode = pstore_get_inode(sb);
431 if (inode) {
432 inode->i_mode = S_IFDIR | 0755;
433 inode->i_op = &pstore_dir_inode_operations;
434 inode->i_fop = &simple_dir_operations;
435 inc_nlink(inode);
436 }
437 sb->s_root = d_make_root(inode);
438 if (!sb->s_root)
439 return -ENOMEM;
440
441 pstore_get_records(0);
442
443 return 0;
444}
445
446static struct dentry *pstore_mount(struct file_system_type *fs_type,
447 int flags, const char *dev_name, void *data)
448{
449 return mount_single(fs_type, flags, data, pstore_fill_super);
450}
451
452static void pstore_kill_sb(struct super_block *sb)
453{
454 kill_litter_super(sb);
455 pstore_sb = NULL;
456}
457
458static struct file_system_type pstore_fs_type = {
459 .owner = THIS_MODULE,
460 .name = "pstore",
461 .mount = pstore_mount,
462 .kill_sb = pstore_kill_sb,
463};
464
465static int __init init_pstore_fs(void)
466{
467 int err;
468
469 /* Create a convenient mount point for people to access pstore */
470 err = sysfs_create_mount_point(fs_kobj, "pstore");
471 if (err)
472 goto out;
473
474 err = register_filesystem(&pstore_fs_type);
475 if (err < 0)
476 sysfs_remove_mount_point(fs_kobj, "pstore");
477
478out:
479 return err;
480}
481module_init(init_pstore_fs)
482
483static void __exit exit_pstore_fs(void)
484{
485 unregister_filesystem(&pstore_fs_type);
486 sysfs_remove_mount_point(fs_kobj, "pstore");
487}
488module_exit(exit_pstore_fs)
489
490MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
491MODULE_LICENSE("GPL");
492
generated by cgit at 2024-05-17 06:29:26 (GMT)