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path: root/fs/pstore/inode.c (plain)
blob: 377485668e0f9e4f76ad0958e2f961601c98dc18
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 ssize_t pstore_file_read(struct file *file, char __user *userbuf,
125 size_t count, loff_t *ppos)
126{
127 struct seq_file *sf = file->private_data;
128 struct pstore_private *ps = sf->private;
129
130 if (ps->type == PSTORE_TYPE_FTRACE)
131 return seq_read(file, userbuf, count, ppos);
132 return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
133}
134
135static int pstore_file_open(struct inode *inode, struct file *file)
136{
137 struct pstore_private *ps = inode->i_private;
138 struct seq_file *sf;
139 int err;
140 const struct seq_operations *sops = NULL;
141
142 if (ps->type == PSTORE_TYPE_FTRACE)
143 sops = &pstore_ftrace_seq_ops;
144
145 err = seq_open(file, sops);
146 if (err < 0)
147 return err;
148
149 sf = file->private_data;
150 sf->private = ps;
151
152 return 0;
153}
154
155static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
156{
157 struct seq_file *sf = file->private_data;
158
159 if (sf->op)
160 return seq_lseek(file, off, whence);
161 return default_llseek(file, off, whence);
162}
163
164static const struct file_operations pstore_file_operations = {
165 .open = pstore_file_open,
166 .read = pstore_file_read,
167 .llseek = pstore_file_llseek,
168 .release = seq_release,
169};
170
171/*
172 * When a file is unlinked from our file system we call the
173 * platform driver to erase the record from persistent store.
174 */
175static int pstore_unlink(struct inode *dir, struct dentry *dentry)
176{
177 struct pstore_private *p = d_inode(dentry)->i_private;
178
179 if (p->psi->erase)
180 p->psi->erase(p->type, p->id, p->count,
181 d_inode(dentry)->i_ctime, p->psi);
182 else
183 return -EPERM;
184
185 return simple_unlink(dir, dentry);
186}
187
188static void pstore_evict_inode(struct inode *inode)
189{
190 struct pstore_private *p = inode->i_private;
191 unsigned long flags;
192
193 clear_inode(inode);
194 if (p) {
195 spin_lock_irqsave(&allpstore_lock, flags);
196 list_del(&p->list);
197 spin_unlock_irqrestore(&allpstore_lock, flags);
198 kfree(p);
199 }
200}
201
202static const struct inode_operations pstore_dir_inode_operations = {
203 .lookup = simple_lookup,
204 .unlink = pstore_unlink,
205};
206
207static struct inode *pstore_get_inode(struct super_block *sb)
208{
209 struct inode *inode = new_inode(sb);
210 if (inode) {
211 inode->i_ino = get_next_ino();
212 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
213 }
214 return inode;
215}
216
217enum {
218 Opt_kmsg_bytes, Opt_err
219};
220
221static const match_table_t tokens = {
222 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
223 {Opt_err, NULL}
224};
225
226static void parse_options(char *options)
227{
228 char *p;
229 substring_t args[MAX_OPT_ARGS];
230 int option;
231
232 if (!options)
233 return;
234
235 while ((p = strsep(&options, ",")) != NULL) {
236 int token;
237
238 if (!*p)
239 continue;
240
241 token = match_token(p, tokens, args);
242 switch (token) {
243 case Opt_kmsg_bytes:
244 if (!match_int(&args[0], &option))
245 pstore_set_kmsg_bytes(option);
246 break;
247 }
248 }
249}
250
251static int pstore_remount(struct super_block *sb, int *flags, char *data)
252{
253 sync_filesystem(sb);
254 parse_options(data);
255
256 return 0;
257}
258
259static const struct super_operations pstore_ops = {
260 .statfs = simple_statfs,
261 .drop_inode = generic_delete_inode,
262 .evict_inode = pstore_evict_inode,
263 .remount_fs = pstore_remount,
264 .show_options = generic_show_options,
265};
266
267static struct super_block *pstore_sb;
268
269bool pstore_is_mounted(void)
270{
271 return pstore_sb != NULL;
272}
273
274/*
275 * Make a regular file in the root directory of our file system.
276 * Load it up with "size" bytes of data from "buf".
277 * Set the mtime & ctime to the date that this record was originally stored.
278 */
279int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
280 char *data, bool compressed, size_t size,
281 struct timespec time, struct pstore_info *psi)
282{
283 struct dentry *root = pstore_sb->s_root;
284 struct dentry *dentry;
285 struct inode *inode;
286 int rc = 0;
287 char name[PSTORE_NAMELEN];
288 struct pstore_private *private, *pos;
289 unsigned long flags;
290
291 spin_lock_irqsave(&allpstore_lock, flags);
292 list_for_each_entry(pos, &allpstore, list) {
293 if (pos->type == type &&
294 pos->id == id &&
295 pos->psi == psi) {
296 rc = -EEXIST;
297 break;
298 }
299 }
300 spin_unlock_irqrestore(&allpstore_lock, flags);
301 if (rc)
302 return rc;
303
304 rc = -ENOMEM;
305 inode = pstore_get_inode(pstore_sb);
306 if (!inode)
307 goto fail;
308 inode->i_mode = S_IFREG | 0444;
309 inode->i_fop = &pstore_file_operations;
310 private = kmalloc(sizeof *private + size, GFP_KERNEL);
311 if (!private)
312 goto fail_alloc;
313 private->type = type;
314 private->id = id;
315 private->count = count;
316 private->psi = psi;
317
318 switch (type) {
319 case PSTORE_TYPE_DMESG:
320 scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
321 psname, id, compressed ? ".enc.z" : "");
322 break;
323 case PSTORE_TYPE_CONSOLE:
324 scnprintf(name, sizeof(name), "console-%s-%lld", psname, id);
325 break;
326 case PSTORE_TYPE_FTRACE:
327 scnprintf(name, sizeof(name), "ftrace-%s-%lld", psname, id);
328 break;
329 case PSTORE_TYPE_MCE:
330 scnprintf(name, sizeof(name), "mce-%s-%lld", psname, id);
331 break;
332 case PSTORE_TYPE_PPC_RTAS:
333 scnprintf(name, sizeof(name), "rtas-%s-%lld", psname, id);
334 break;
335 case PSTORE_TYPE_PPC_OF:
336 scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
337 psname, id);
338 break;
339 case PSTORE_TYPE_PPC_COMMON:
340 scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
341 psname, id);
342 break;
343 case PSTORE_TYPE_PMSG:
344 scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id);
345 break;
346 case PSTORE_TYPE_PPC_OPAL:
347 sprintf(name, "powerpc-opal-%s-%lld", psname, id);
348 break;
349 case PSTORE_TYPE_UNKNOWN:
350 scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id);
351 break;
352 default:
353 scnprintf(name, sizeof(name), "type%d-%s-%lld",
354 type, psname, id);
355 break;
356 }
357
358 inode_lock(d_inode(root));
359
360 dentry = d_alloc_name(root, name);
361 if (!dentry)
362 goto fail_lockedalloc;
363
364 memcpy(private->data, data, size);
365 inode->i_size = private->size = size;
366
367 inode->i_private = private;
368
369 if (time.tv_sec)
370 inode->i_mtime = inode->i_ctime = time;
371
372 d_add(dentry, inode);
373
374 spin_lock_irqsave(&allpstore_lock, flags);
375 list_add(&private->list, &allpstore);
376 spin_unlock_irqrestore(&allpstore_lock, flags);
377
378 inode_unlock(d_inode(root));
379
380 return 0;
381
382fail_lockedalloc:
383 inode_unlock(d_inode(root));
384 kfree(private);
385fail_alloc:
386 iput(inode);
387
388fail:
389 return rc;
390}
391
392static int pstore_fill_super(struct super_block *sb, void *data, int silent)
393{
394 struct inode *inode;
395
396 save_mount_options(sb, data);
397
398 pstore_sb = sb;
399
400 sb->s_maxbytes = MAX_LFS_FILESIZE;
401 sb->s_blocksize = PAGE_SIZE;
402 sb->s_blocksize_bits = PAGE_SHIFT;
403 sb->s_magic = PSTOREFS_MAGIC;
404 sb->s_op = &pstore_ops;
405 sb->s_time_gran = 1;
406
407 parse_options(data);
408
409 inode = pstore_get_inode(sb);
410 if (inode) {
411 inode->i_mode = S_IFDIR | 0755;
412 inode->i_op = &pstore_dir_inode_operations;
413 inode->i_fop = &simple_dir_operations;
414 inc_nlink(inode);
415 }
416 sb->s_root = d_make_root(inode);
417 if (!sb->s_root)
418 return -ENOMEM;
419
420 pstore_get_records(0);
421
422 return 0;
423}
424
425static struct dentry *pstore_mount(struct file_system_type *fs_type,
426 int flags, const char *dev_name, void *data)
427{
428 return mount_single(fs_type, flags, data, pstore_fill_super);
429}
430
431static void pstore_kill_sb(struct super_block *sb)
432{
433 kill_litter_super(sb);
434 pstore_sb = NULL;
435}
436
437static struct file_system_type pstore_fs_type = {
438 .owner = THIS_MODULE,
439 .name = "pstore",
440 .mount = pstore_mount,
441 .kill_sb = pstore_kill_sb,
442};
443
444static int __init init_pstore_fs(void)
445{
446 int err;
447
448 /* Create a convenient mount point for people to access pstore */
449 err = sysfs_create_mount_point(fs_kobj, "pstore");
450 if (err)
451 goto out;
452
453 err = register_filesystem(&pstore_fs_type);
454 if (err < 0)
455 sysfs_remove_mount_point(fs_kobj, "pstore");
456
457out:
458 return err;
459}
460module_init(init_pstore_fs)
461
462static void __exit exit_pstore_fs(void)
463{
464 unregister_filesystem(&pstore_fs_type);
465 sysfs_remove_mount_point(fs_kobj, "pstore");
466}
467module_exit(exit_pstore_fs)
468
469MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
470MODULE_LICENSE("GPL");
471
generated by cgit at 2024-05-17 02:03:18 (GMT)