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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 .owner = THIS_MODULE,
182 .open = pstore_file_open,
183 .read = pstore_file_read,
184 .llseek = pstore_file_llseek,
185 .release = seq_release,
186};
187
188/*
189 * When a file is unlinked from our file system we call the
190 * platform driver to erase the record from persistent store.
191 */
192static int pstore_unlink(struct inode *dir, struct dentry *dentry)
193{
194 struct pstore_private *p = d_inode(dentry)->i_private;
195 int err;
196
197 err = pstore_check_syslog_permissions(p);
198 if (err)
199 return err;
200
201 if (p->psi->erase)
202 p->psi->erase(p->type, p->id, p->count,
203 d_inode(dentry)->i_ctime, p->psi);
204 else
205 return -EPERM;
206
207 return simple_unlink(dir, dentry);
208}
209
210static void pstore_evict_inode(struct inode *inode)
211{
212 struct pstore_private *p = inode->i_private;
213 unsigned long flags;
214
215 clear_inode(inode);
216 if (p) {
217 spin_lock_irqsave(&allpstore_lock, flags);
218 list_del(&p->list);
219 spin_unlock_irqrestore(&allpstore_lock, flags);
220 kfree(p);
221 }
222}
223
224static const struct inode_operations pstore_dir_inode_operations = {
225 .lookup = simple_lookup,
226 .unlink = pstore_unlink,
227};
228
229static struct inode *pstore_get_inode(struct super_block *sb)
230{
231 struct inode *inode = new_inode(sb);
232 if (inode) {
233 inode->i_ino = get_next_ino();
234 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
235 }
236 return inode;
237}
238
239enum {
240 Opt_kmsg_bytes, Opt_err
241};
242
243static const match_table_t tokens = {
244 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
245 {Opt_err, NULL}
246};
247
248static void parse_options(char *options)
249{
250 char *p;
251 substring_t args[MAX_OPT_ARGS];
252 int option;
253
254 if (!options)
255 return;
256
257 while ((p = strsep(&options, ",")) != NULL) {
258 int token;
259
260 if (!*p)
261 continue;
262
263 token = match_token(p, tokens, args);
264 switch (token) {
265 case Opt_kmsg_bytes:
266 if (!match_int(&args[0], &option))
267 pstore_set_kmsg_bytes(option);
268 break;
269 }
270 }
271}
272
273static int pstore_remount(struct super_block *sb, int *flags, char *data)
274{
275 sync_filesystem(sb);
276 parse_options(data);
277
278 return 0;
279}
280
281static const struct super_operations pstore_ops = {
282 .statfs = simple_statfs,
283 .drop_inode = generic_delete_inode,
284 .evict_inode = pstore_evict_inode,
285 .remount_fs = pstore_remount,
286 .show_options = generic_show_options,
287};
288
289static struct super_block *pstore_sb;
290
291bool pstore_is_mounted(void)
292{
293 return pstore_sb != NULL;
294}
295
296/*
297 * Make a regular file in the root directory of our file system.
298 * Load it up with "size" bytes of data from "buf".
299 * Set the mtime & ctime to the date that this record was originally stored.
300 */
301int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
302 char *data, bool compressed, size_t size,
303 struct timespec time, struct pstore_info *psi)
304{
305 struct dentry *root = pstore_sb->s_root;
306 struct dentry *dentry;
307 struct inode *inode;
308 int rc = 0;
309 char name[PSTORE_NAMELEN];
310 struct pstore_private *private, *pos;
311 unsigned long flags;
312
313 spin_lock_irqsave(&allpstore_lock, flags);
314 list_for_each_entry(pos, &allpstore, list) {
315 if (pos->type == type &&
316 pos->id == id &&
317 pos->psi == psi) {
318 rc = -EEXIST;
319 break;
320 }
321 }
322 spin_unlock_irqrestore(&allpstore_lock, flags);
323 if (rc)
324 return rc;
325
326 rc = -ENOMEM;
327 inode = pstore_get_inode(pstore_sb);
328 if (!inode)
329 goto fail;
330 inode->i_mode = S_IFREG | 0444;
331 inode->i_fop = &pstore_file_operations;
332 private = kmalloc(sizeof *private + size, GFP_KERNEL);
333 if (!private)
334 goto fail_alloc;
335 private->type = type;
336 private->id = id;
337 private->count = count;
338 private->psi = psi;
339
340 switch (type) {
341 case PSTORE_TYPE_DMESG:
342 scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
343 psname, id, compressed ? ".enc.z" : "");
344 break;
345 case PSTORE_TYPE_CONSOLE:
346 scnprintf(name, sizeof(name), "console-%s-%lld", psname, id);
347 break;
348 case PSTORE_TYPE_FTRACE:
349 scnprintf(name, sizeof(name), "ftrace-%s-%lld", psname, id);
350 break;
351 case PSTORE_TYPE_MCE:
352 scnprintf(name, sizeof(name), "mce-%s-%lld", psname, id);
353 break;
354 case PSTORE_TYPE_PPC_RTAS:
355 scnprintf(name, sizeof(name), "rtas-%s-%lld", psname, id);
356 break;
357 case PSTORE_TYPE_PPC_OF:
358 scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
359 psname, id);
360 break;
361 case PSTORE_TYPE_PPC_COMMON:
362 scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
363 psname, id);
364 break;
365 case PSTORE_TYPE_PMSG:
366 scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id);
367 break;
368 case PSTORE_TYPE_PPC_OPAL:
369 sprintf(name, "powerpc-opal-%s-%lld", psname, id);
370 break;
371 case PSTORE_TYPE_UNKNOWN:
372 scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id);
373 break;
374 default:
375 scnprintf(name, sizeof(name), "type%d-%s-%lld",
376 type, psname, id);
377 break;
378 }
379
380 inode_lock(d_inode(root));
381
382 dentry = d_alloc_name(root, name);
383 if (!dentry)
384 goto fail_lockedalloc;
385
386 memcpy(private->data, data, size);
387 inode->i_size = private->size = size;
388
389 inode->i_private = private;
390
391 if (time.tv_sec)
392 inode->i_mtime = inode->i_ctime = time;
393
394 d_add(dentry, inode);
395
396 spin_lock_irqsave(&allpstore_lock, flags);
397 list_add(&private->list, &allpstore);
398 spin_unlock_irqrestore(&allpstore_lock, flags);
399
400 inode_unlock(d_inode(root));
401
402 return 0;
403
404fail_lockedalloc:
405 inode_unlock(d_inode(root));
406 kfree(private);
407fail_alloc:
408 iput(inode);
409
410fail:
411 return rc;
412}
413
414static int pstore_fill_super(struct super_block *sb, void *data, int silent)
415{
416 struct inode *inode;
417
418 save_mount_options(sb, data);
419
420 pstore_sb = sb;
421
422 sb->s_maxbytes = MAX_LFS_FILESIZE;
423 sb->s_blocksize = PAGE_SIZE;
424 sb->s_blocksize_bits = PAGE_SHIFT;
425 sb->s_magic = PSTOREFS_MAGIC;
426 sb->s_op = &pstore_ops;
427 sb->s_time_gran = 1;
428
429 parse_options(data);
430
431 inode = pstore_get_inode(sb);
432 if (inode) {
433 inode->i_mode = S_IFDIR | 0755;
434 inode->i_op = &pstore_dir_inode_operations;
435 inode->i_fop = &simple_dir_operations;
436 inc_nlink(inode);
437 }
438 sb->s_root = d_make_root(inode);
439 if (!sb->s_root)
440 return -ENOMEM;
441
442 pstore_get_records(0);
443
444 return 0;
445}
446
447static struct dentry *pstore_mount(struct file_system_type *fs_type,
448 int flags, const char *dev_name, void *data)
449{
450 return mount_single(fs_type, flags, data, pstore_fill_super);
451}
452
453static void pstore_kill_sb(struct super_block *sb)
454{
455 kill_litter_super(sb);
456 pstore_sb = NULL;
457}
458
459static struct file_system_type pstore_fs_type = {
460 .owner = THIS_MODULE,
461 .name = "pstore",
462 .mount = pstore_mount,
463 .kill_sb = pstore_kill_sb,
464};
465
466static int __init init_pstore_fs(void)
467{
468 int err;
469
470 /* Create a convenient mount point for people to access pstore */
471 err = sysfs_create_mount_point(fs_kobj, "pstore");
472 if (err)
473 goto out;
474
475 err = register_filesystem(&pstore_fs_type);
476 if (err < 0)
477 sysfs_remove_mount_point(fs_kobj, "pstore");
478
479out:
480 return err;
481}
482module_init(init_pstore_fs)
483
484static void __exit exit_pstore_fs(void)
485{
486 unregister_filesystem(&pstore_fs_type);
487 sysfs_remove_mount_point(fs_kobj, "pstore");
488}
489module_exit(exit_pstore_fs)
490
491MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
492MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Persistent Storage - ramfs parts.
4 *
5 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
6 */
7
8#include <linux/module.h>
9#include <linux/fs.h>
10#include <linux/fsnotify.h>
11#include <linux/pagemap.h>
12#include <linux/highmem.h>
13#include <linux/time.h>
14#include <linux/init.h>
15#include <linux/list.h>
16#include <linux/string.h>
17#include <linux/mount.h>
18#include <linux/seq_file.h>
19#include <linux/ramfs.h>
20#include <linux/parser.h>
21#include <linux/sched.h>
22#include <linux/magic.h>
23#include <linux/pstore.h>
24#include <linux/slab.h>
25#include <linux/uaccess.h>
26#include <linux/cleanup.h>
27
28#include "internal.h"
29
30#define PSTORE_NAMELEN 64
31
32static DEFINE_MUTEX(records_list_lock);
33static LIST_HEAD(records_list);
34
35static DEFINE_MUTEX(pstore_sb_lock);
36static struct super_block *pstore_sb;
37
38DEFINE_FREE(pstore_iput, struct inode *, if (_T) iput(_T))
39
40struct pstore_private {
41 struct list_head list;
42 struct dentry *dentry;
43 struct pstore_record *record;
44 size_t total_size;
45};
46
47struct pstore_ftrace_seq_data {
48 const void *ptr;
49 size_t off;
50 size_t size;
51};
52
53#define REC_SIZE sizeof(struct pstore_ftrace_record)
54
55static void free_pstore_private(struct pstore_private *private)
56{
57 if (!private)
58 return;
59 if (private->record) {
60 kvfree(private->record->buf);
61 kfree(private->record->priv);
62 kfree(private->record);
63 }
64 kfree(private);
65}
66DEFINE_FREE(pstore_private, struct pstore_private *, free_pstore_private(_T));
67
68static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
69{
70 struct pstore_private *ps = s->private;
71 struct pstore_ftrace_seq_data *data __free(kfree) = NULL;
72
73 data = kzalloc(sizeof(*data), GFP_KERNEL);
74 if (!data)
75 return NULL;
76
77 data->off = ps->total_size % REC_SIZE;
78 data->off += *pos * REC_SIZE;
79 if (data->off + REC_SIZE > ps->total_size)
80 return NULL;
81
82 return_ptr(data);
83}
84
85static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
86{
87 kfree(v);
88}
89
90static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
91{
92 struct pstore_private *ps = s->private;
93 struct pstore_ftrace_seq_data *data = v;
94
95 (*pos)++;
96 data->off += REC_SIZE;
97 if (data->off + REC_SIZE > ps->total_size)
98 return NULL;
99
100 return data;
101}
102
103static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
104{
105 struct pstore_private *ps = s->private;
106 struct pstore_ftrace_seq_data *data = v;
107 struct pstore_ftrace_record *rec;
108
109 if (!data)
110 return 0;
111
112 rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
113
114 seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %ps <- %pS\n",
115 pstore_ftrace_decode_cpu(rec),
116 pstore_ftrace_read_timestamp(rec),
117 rec->ip, rec->parent_ip, (void *)rec->ip,
118 (void *)rec->parent_ip);
119
120 return 0;
121}
122
123static const struct seq_operations pstore_ftrace_seq_ops = {
124 .start = pstore_ftrace_seq_start,
125 .next = pstore_ftrace_seq_next,
126 .stop = pstore_ftrace_seq_stop,
127 .show = pstore_ftrace_seq_show,
128};
129
130static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
131 size_t count, loff_t *ppos)
132{
133 struct seq_file *sf = file->private_data;
134 struct pstore_private *ps = sf->private;
135
136 if (ps->record->type == PSTORE_TYPE_FTRACE)
137 return seq_read(file, userbuf, count, ppos);
138 return simple_read_from_buffer(userbuf, count, ppos,
139 ps->record->buf, ps->total_size);
140}
141
142static int pstore_file_open(struct inode *inode, struct file *file)
143{
144 struct pstore_private *ps = inode->i_private;
145 struct seq_file *sf;
146 int err;
147 const struct seq_operations *sops = NULL;
148
149 if (ps->record->type == PSTORE_TYPE_FTRACE)
150 sops = &pstore_ftrace_seq_ops;
151
152 err = seq_open(file, sops);
153 if (err < 0)
154 return err;
155
156 sf = file->private_data;
157 sf->private = ps;
158
159 return 0;
160}
161
162static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
163{
164 struct seq_file *sf = file->private_data;
165
166 if (sf->op)
167 return seq_lseek(file, off, whence);
168 return default_llseek(file, off, whence);
169}
170
171static const struct file_operations pstore_file_operations = {
172 .open = pstore_file_open,
173 .read = pstore_file_read,
174 .llseek = pstore_file_llseek,
175 .release = seq_release,
176};
177
178/*
179 * When a file is unlinked from our file system we call the
180 * platform driver to erase the record from persistent store.
181 */
182static int pstore_unlink(struct inode *dir, struct dentry *dentry)
183{
184 struct pstore_private *p = d_inode(dentry)->i_private;
185 struct pstore_record *record = p->record;
186
187 if (!record->psi->erase)
188 return -EPERM;
189
190 /* Make sure we can't race while removing this file. */
191 scoped_guard(mutex, &records_list_lock) {
192 if (!list_empty(&p->list))
193 list_del_init(&p->list);
194 else
195 return -ENOENT;
196 p->dentry = NULL;
197 }
198
199 scoped_guard(mutex, &record->psi->read_mutex)
200 record->psi->erase(record);
201
202 return simple_unlink(dir, dentry);
203}
204
205static void pstore_evict_inode(struct inode *inode)
206{
207 struct pstore_private *p = inode->i_private;
208
209 clear_inode(inode);
210 free_pstore_private(p);
211}
212
213static const struct inode_operations pstore_dir_inode_operations = {
214 .lookup = simple_lookup,
215 .unlink = pstore_unlink,
216};
217
218static struct inode *pstore_get_inode(struct super_block *sb)
219{
220 struct inode *inode = new_inode(sb);
221 if (inode) {
222 inode->i_ino = get_next_ino();
223 simple_inode_init_ts(inode);
224 }
225 return inode;
226}
227
228enum {
229 Opt_kmsg_bytes, Opt_err
230};
231
232static const match_table_t tokens = {
233 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
234 {Opt_err, NULL}
235};
236
237static void parse_options(char *options)
238{
239 char *p;
240 substring_t args[MAX_OPT_ARGS];
241 int option;
242
243 if (!options)
244 return;
245
246 while ((p = strsep(&options, ",")) != NULL) {
247 int token;
248
249 if (!*p)
250 continue;
251
252 token = match_token(p, tokens, args);
253 switch (token) {
254 case Opt_kmsg_bytes:
255 if (!match_int(&args[0], &option))
256 pstore_set_kmsg_bytes(option);
257 break;
258 }
259 }
260}
261
262/*
263 * Display the mount options in /proc/mounts.
264 */
265static int pstore_show_options(struct seq_file *m, struct dentry *root)
266{
267 if (kmsg_bytes != CONFIG_PSTORE_DEFAULT_KMSG_BYTES)
268 seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes);
269 return 0;
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 = pstore_show_options,
286};
287
288static struct dentry *psinfo_lock_root(void)
289{
290 struct dentry *root;
291
292 guard(mutex)(&pstore_sb_lock);
293 /*
294 * Having no backend is fine -- no records appear.
295 * Not being mounted is fine -- nothing to do.
296 */
297 if (!psinfo || !pstore_sb)
298 return NULL;
299
300 root = pstore_sb->s_root;
301 inode_lock(d_inode(root));
302
303 return root;
304}
305
306int pstore_put_backend_records(struct pstore_info *psi)
307{
308 struct pstore_private *pos, *tmp;
309 struct dentry *root;
310
311 root = psinfo_lock_root();
312 if (!root)
313 return 0;
314
315 scoped_guard(mutex, &records_list_lock) {
316 list_for_each_entry_safe(pos, tmp, &records_list, list) {
317 if (pos->record->psi == psi) {
318 list_del_init(&pos->list);
319 d_invalidate(pos->dentry);
320 simple_unlink(d_inode(root), pos->dentry);
321 pos->dentry = NULL;
322 }
323 }
324 }
325
326 inode_unlock(d_inode(root));
327
328 return 0;
329}
330
331/*
332 * Make a regular file in the root directory of our file system.
333 * Load it up with "size" bytes of data from "buf".
334 * Set the mtime & ctime to the date that this record was originally stored.
335 */
336int pstore_mkfile(struct dentry *root, struct pstore_record *record)
337{
338 struct dentry *dentry;
339 struct inode *inode __free(pstore_iput) = NULL;
340 char name[PSTORE_NAMELEN];
341 struct pstore_private *private __free(pstore_private) = NULL, *pos;
342 size_t size = record->size + record->ecc_notice_size;
343
344 if (WARN_ON(!inode_is_locked(d_inode(root))))
345 return -EINVAL;
346
347 guard(mutex)(&records_list_lock);
348
349 /* Skip records that are already present in the filesystem. */
350 list_for_each_entry(pos, &records_list, list) {
351 if (pos->record->type == record->type &&
352 pos->record->id == record->id &&
353 pos->record->psi == record->psi)
354 return -EEXIST;
355 }
356
357 inode = pstore_get_inode(root->d_sb);
358 if (!inode)
359 return -ENOMEM;
360 inode->i_mode = S_IFREG | 0444;
361 inode->i_fop = &pstore_file_operations;
362 scnprintf(name, sizeof(name), "%s-%s-%llu%s",
363 pstore_type_to_name(record->type),
364 record->psi->name, record->id,
365 record->compressed ? ".enc.z" : "");
366
367 private = kzalloc(sizeof(*private), GFP_KERNEL);
368 if (!private)
369 return -ENOMEM;
370
371 dentry = d_alloc_name(root, name);
372 if (!dentry)
373 return -ENOMEM;
374
375 private->dentry = dentry;
376 private->record = record;
377 inode->i_size = private->total_size = size;
378 inode->i_private = private;
379
380 if (record->time.tv_sec)
381 inode_set_mtime_to_ts(inode,
382 inode_set_ctime_to_ts(inode, record->time));
383
384 d_add(dentry, no_free_ptr(inode));
385
386 list_add(&(no_free_ptr(private))->list, &records_list);
387
388 return 0;
389}
390
391/*
392 * Read all the records from the persistent store. Create
393 * files in our filesystem. Don't warn about -EEXIST errors
394 * when we are re-scanning the backing store looking to add new
395 * error records.
396 */
397void pstore_get_records(int quiet)
398{
399 struct dentry *root;
400
401 root = psinfo_lock_root();
402 if (!root)
403 return;
404
405 pstore_get_backend_records(psinfo, root, quiet);
406 inode_unlock(d_inode(root));
407}
408
409static int pstore_fill_super(struct super_block *sb, void *data, int silent)
410{
411 struct inode *inode;
412
413 sb->s_maxbytes = MAX_LFS_FILESIZE;
414 sb->s_blocksize = PAGE_SIZE;
415 sb->s_blocksize_bits = PAGE_SHIFT;
416 sb->s_magic = PSTOREFS_MAGIC;
417 sb->s_op = &pstore_ops;
418 sb->s_time_gran = 1;
419
420 parse_options(data);
421
422 inode = pstore_get_inode(sb);
423 if (inode) {
424 inode->i_mode = S_IFDIR | 0750;
425 inode->i_op = &pstore_dir_inode_operations;
426 inode->i_fop = &simple_dir_operations;
427 inc_nlink(inode);
428 }
429 sb->s_root = d_make_root(inode);
430 if (!sb->s_root)
431 return -ENOMEM;
432
433 scoped_guard(mutex, &pstore_sb_lock)
434 pstore_sb = sb;
435
436 pstore_get_records(0);
437
438 return 0;
439}
440
441static struct dentry *pstore_mount(struct file_system_type *fs_type,
442 int flags, const char *dev_name, void *data)
443{
444 return mount_single(fs_type, flags, data, pstore_fill_super);
445}
446
447static void pstore_kill_sb(struct super_block *sb)
448{
449 guard(mutex)(&pstore_sb_lock);
450 WARN_ON(pstore_sb && pstore_sb != sb);
451
452 kill_litter_super(sb);
453 pstore_sb = NULL;
454
455 guard(mutex)(&records_list_lock);
456 INIT_LIST_HEAD(&records_list);
457}
458
459static struct file_system_type pstore_fs_type = {
460 .owner = THIS_MODULE,
461 .name = "pstore",
462 .mount = pstore_mount,
463 .kill_sb = pstore_kill_sb,
464};
465
466int __init pstore_init_fs(void)
467{
468 int err;
469
470 /* Create a convenient mount point for people to access pstore */
471 err = sysfs_create_mount_point(fs_kobj, "pstore");
472 if (err)
473 goto out;
474
475 err = register_filesystem(&pstore_fs_type);
476 if (err < 0)
477 sysfs_remove_mount_point(fs_kobj, "pstore");
478
479out:
480 return err;
481}
482
483void __exit pstore_exit_fs(void)
484{
485 unregister_filesystem(&pstore_fs_type);
486 sysfs_remove_mount_point(fs_kobj, "pstore");
487}