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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/spinlock.h>
26#include <linux/uaccess.h>
27
28#include "internal.h"
29
30#define PSTORE_NAMELEN 64
31
32static DEFINE_SPINLOCK(allpstore_lock);
33static LIST_HEAD(allpstore);
34
35struct pstore_private {
36 struct list_head list;
37 struct pstore_record *record;
38 size_t total_size;
39};
40
41struct pstore_ftrace_seq_data {
42 const void *ptr;
43 size_t off;
44 size_t size;
45};
46
47#define REC_SIZE sizeof(struct pstore_ftrace_record)
48
49static void free_pstore_private(struct pstore_private *private)
50{
51 if (!private)
52 return;
53 if (private->record) {
54 kfree(private->record->buf);
55 kfree(private->record);
56 }
57 kfree(private);
58}
59
60static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
61{
62 struct pstore_private *ps = s->private;
63 struct pstore_ftrace_seq_data *data;
64
65 data = kzalloc(sizeof(*data), GFP_KERNEL);
66 if (!data)
67 return NULL;
68
69 data->off = ps->total_size % REC_SIZE;
70 data->off += *pos * REC_SIZE;
71 if (data->off + REC_SIZE > ps->total_size) {
72 kfree(data);
73 return NULL;
74 }
75
76 return data;
77
78}
79
80static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
81{
82 kfree(v);
83}
84
85static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
86{
87 struct pstore_private *ps = s->private;
88 struct pstore_ftrace_seq_data *data = v;
89
90 data->off += REC_SIZE;
91 if (data->off + REC_SIZE > ps->total_size)
92 return NULL;
93
94 (*pos)++;
95 return data;
96}
97
98static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
99{
100 struct pstore_private *ps = s->private;
101 struct pstore_ftrace_seq_data *data = v;
102 struct pstore_ftrace_record *rec;
103
104 rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
105
106 seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %ps <- %pS\n",
107 pstore_ftrace_decode_cpu(rec),
108 pstore_ftrace_read_timestamp(rec),
109 rec->ip, rec->parent_ip, (void *)rec->ip,
110 (void *)rec->parent_ip);
111
112 return 0;
113}
114
115static const struct seq_operations pstore_ftrace_seq_ops = {
116 .start = pstore_ftrace_seq_start,
117 .next = pstore_ftrace_seq_next,
118 .stop = pstore_ftrace_seq_stop,
119 .show = pstore_ftrace_seq_show,
120};
121
122static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
123 size_t count, loff_t *ppos)
124{
125 struct seq_file *sf = file->private_data;
126 struct pstore_private *ps = sf->private;
127
128 if (ps->record->type == PSTORE_TYPE_FTRACE)
129 return seq_read(file, userbuf, count, ppos);
130 return simple_read_from_buffer(userbuf, count, ppos,
131 ps->record->buf, ps->total_size);
132}
133
134static int pstore_file_open(struct inode *inode, struct file *file)
135{
136 struct pstore_private *ps = inode->i_private;
137 struct seq_file *sf;
138 int err;
139 const struct seq_operations *sops = NULL;
140
141 if (ps->record->type == PSTORE_TYPE_FTRACE)
142 sops = &pstore_ftrace_seq_ops;
143
144 err = seq_open(file, sops);
145 if (err < 0)
146 return err;
147
148 sf = file->private_data;
149 sf->private = ps;
150
151 return 0;
152}
153
154static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
155{
156 struct seq_file *sf = file->private_data;
157
158 if (sf->op)
159 return seq_lseek(file, off, whence);
160 return default_llseek(file, off, whence);
161}
162
163static const struct file_operations pstore_file_operations = {
164 .open = pstore_file_open,
165 .read = pstore_file_read,
166 .llseek = pstore_file_llseek,
167 .release = seq_release,
168};
169
170/*
171 * When a file is unlinked from our file system we call the
172 * platform driver to erase the record from persistent store.
173 */
174static int pstore_unlink(struct inode *dir, struct dentry *dentry)
175{
176 struct pstore_private *p = d_inode(dentry)->i_private;
177 struct pstore_record *record = p->record;
178
179 if (!record->psi->erase)
180 return -EPERM;
181
182 mutex_lock(&record->psi->read_mutex);
183 record->psi->erase(record);
184 mutex_unlock(&record->psi->read_mutex);
185
186 return simple_unlink(dir, dentry);
187}
188
189static void pstore_evict_inode(struct inode *inode)
190{
191 struct pstore_private *p = inode->i_private;
192 unsigned long flags;
193
194 clear_inode(inode);
195 if (p) {
196 spin_lock_irqsave(&allpstore_lock, flags);
197 list_del(&p->list);
198 spin_unlock_irqrestore(&allpstore_lock, flags);
199 free_pstore_private(p);
200 }
201}
202
203static const struct inode_operations pstore_dir_inode_operations = {
204 .lookup = simple_lookup,
205 .unlink = pstore_unlink,
206};
207
208static struct inode *pstore_get_inode(struct super_block *sb)
209{
210 struct inode *inode = new_inode(sb);
211 if (inode) {
212 inode->i_ino = get_next_ino();
213 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
214 }
215 return inode;
216}
217
218enum {
219 Opt_kmsg_bytes, Opt_err
220};
221
222static const match_table_t tokens = {
223 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
224 {Opt_err, NULL}
225};
226
227static void parse_options(char *options)
228{
229 char *p;
230 substring_t args[MAX_OPT_ARGS];
231 int option;
232
233 if (!options)
234 return;
235
236 while ((p = strsep(&options, ",")) != NULL) {
237 int token;
238
239 if (!*p)
240 continue;
241
242 token = match_token(p, tokens, args);
243 switch (token) {
244 case Opt_kmsg_bytes:
245 if (!match_int(&args[0], &option))
246 pstore_set_kmsg_bytes(option);
247 break;
248 }
249 }
250}
251
252/*
253 * Display the mount options in /proc/mounts.
254 */
255static int pstore_show_options(struct seq_file *m, struct dentry *root)
256{
257 if (kmsg_bytes != PSTORE_DEFAULT_KMSG_BYTES)
258 seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes);
259 return 0;
260}
261
262static int pstore_remount(struct super_block *sb, int *flags, char *data)
263{
264 sync_filesystem(sb);
265 parse_options(data);
266
267 return 0;
268}
269
270static const struct super_operations pstore_ops = {
271 .statfs = simple_statfs,
272 .drop_inode = generic_delete_inode,
273 .evict_inode = pstore_evict_inode,
274 .remount_fs = pstore_remount,
275 .show_options = pstore_show_options,
276};
277
278static struct super_block *pstore_sb;
279
280bool pstore_is_mounted(void)
281{
282 return pstore_sb != NULL;
283}
284
285/*
286 * Make a regular file in the root directory of our file system.
287 * Load it up with "size" bytes of data from "buf".
288 * Set the mtime & ctime to the date that this record was originally stored.
289 */
290int pstore_mkfile(struct dentry *root, struct pstore_record *record)
291{
292 struct dentry *dentry;
293 struct inode *inode;
294 int rc = 0;
295 char name[PSTORE_NAMELEN];
296 struct pstore_private *private, *pos;
297 unsigned long flags;
298 size_t size = record->size + record->ecc_notice_size;
299
300 WARN_ON(!inode_is_locked(d_inode(root)));
301
302 spin_lock_irqsave(&allpstore_lock, flags);
303 list_for_each_entry(pos, &allpstore, list) {
304 if (pos->record->type == record->type &&
305 pos->record->id == record->id &&
306 pos->record->psi == record->psi) {
307 rc = -EEXIST;
308 break;
309 }
310 }
311 spin_unlock_irqrestore(&allpstore_lock, flags);
312 if (rc)
313 return rc;
314
315 rc = -ENOMEM;
316 inode = pstore_get_inode(root->d_sb);
317 if (!inode)
318 goto fail;
319 inode->i_mode = S_IFREG | 0444;
320 inode->i_fop = &pstore_file_operations;
321 scnprintf(name, sizeof(name), "%s-%s-%llu%s",
322 pstore_type_to_name(record->type),
323 record->psi->name, record->id,
324 record->compressed ? ".enc.z" : "");
325
326 private = kzalloc(sizeof(*private), GFP_KERNEL);
327 if (!private)
328 goto fail_inode;
329
330 dentry = d_alloc_name(root, name);
331 if (!dentry)
332 goto fail_private;
333
334 private->record = record;
335 inode->i_size = private->total_size = size;
336 inode->i_private = private;
337
338 if (record->time.tv_sec)
339 inode->i_mtime = inode->i_ctime = record->time;
340
341 d_add(dentry, inode);
342
343 spin_lock_irqsave(&allpstore_lock, flags);
344 list_add(&private->list, &allpstore);
345 spin_unlock_irqrestore(&allpstore_lock, flags);
346
347 return 0;
348
349fail_private:
350 free_pstore_private(private);
351fail_inode:
352 iput(inode);
353
354fail:
355 return rc;
356}
357
358/*
359 * Read all the records from the persistent store. Create
360 * files in our filesystem. Don't warn about -EEXIST errors
361 * when we are re-scanning the backing store looking to add new
362 * error records.
363 */
364void pstore_get_records(int quiet)
365{
366 struct pstore_info *psi = psinfo;
367 struct dentry *root;
368
369 if (!psi || !pstore_sb)
370 return;
371
372 root = pstore_sb->s_root;
373
374 inode_lock(d_inode(root));
375 pstore_get_backend_records(psi, root, quiet);
376 inode_unlock(d_inode(root));
377}
378
379static int pstore_fill_super(struct super_block *sb, void *data, int silent)
380{
381 struct inode *inode;
382
383 pstore_sb = sb;
384
385 sb->s_maxbytes = MAX_LFS_FILESIZE;
386 sb->s_blocksize = PAGE_SIZE;
387 sb->s_blocksize_bits = PAGE_SHIFT;
388 sb->s_magic = PSTOREFS_MAGIC;
389 sb->s_op = &pstore_ops;
390 sb->s_time_gran = 1;
391
392 parse_options(data);
393
394 inode = pstore_get_inode(sb);
395 if (inode) {
396 inode->i_mode = S_IFDIR | 0750;
397 inode->i_op = &pstore_dir_inode_operations;
398 inode->i_fop = &simple_dir_operations;
399 inc_nlink(inode);
400 }
401 sb->s_root = d_make_root(inode);
402 if (!sb->s_root)
403 return -ENOMEM;
404
405 pstore_get_records(0);
406
407 return 0;
408}
409
410static struct dentry *pstore_mount(struct file_system_type *fs_type,
411 int flags, const char *dev_name, void *data)
412{
413 return mount_single(fs_type, flags, data, pstore_fill_super);
414}
415
416static void pstore_kill_sb(struct super_block *sb)
417{
418 kill_litter_super(sb);
419 pstore_sb = NULL;
420}
421
422static struct file_system_type pstore_fs_type = {
423 .owner = THIS_MODULE,
424 .name = "pstore",
425 .mount = pstore_mount,
426 .kill_sb = pstore_kill_sb,
427};
428
429int __init pstore_init_fs(void)
430{
431 int err;
432
433 /* Create a convenient mount point for people to access pstore */
434 err = sysfs_create_mount_point(fs_kobj, "pstore");
435 if (err)
436 goto out;
437
438 err = register_filesystem(&pstore_fs_type);
439 if (err < 0)
440 sysfs_remove_mount_point(fs_kobj, "pstore");
441
442out:
443 return err;
444}
445
446void __exit pstore_exit_fs(void)
447{
448 unregister_filesystem(&pstore_fs_type);
449 sysfs_remove_mount_point(fs_kobj, "pstore");
450}
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
27#include "internal.h"
28
29#define PSTORE_NAMELEN 64
30
31static DEFINE_MUTEX(records_list_lock);
32static LIST_HEAD(records_list);
33
34static DEFINE_MUTEX(pstore_sb_lock);
35static struct super_block *pstore_sb;
36
37struct pstore_private {
38 struct list_head list;
39 struct dentry *dentry;
40 struct pstore_record *record;
41 size_t total_size;
42};
43
44struct pstore_ftrace_seq_data {
45 const void *ptr;
46 size_t off;
47 size_t size;
48};
49
50#define REC_SIZE sizeof(struct pstore_ftrace_record)
51
52static void free_pstore_private(struct pstore_private *private)
53{
54 if (!private)
55 return;
56 if (private->record) {
57 kfree(private->record->buf);
58 kfree(private->record->priv);
59 kfree(private->record);
60 }
61 kfree(private);
62}
63
64static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
65{
66 struct pstore_private *ps = s->private;
67 struct pstore_ftrace_seq_data *data;
68
69 data = kzalloc(sizeof(*data), GFP_KERNEL);
70 if (!data)
71 return NULL;
72
73 data->off = ps->total_size % REC_SIZE;
74 data->off += *pos * REC_SIZE;
75 if (data->off + REC_SIZE > ps->total_size) {
76 kfree(data);
77 return NULL;
78 }
79
80 return data;
81
82}
83
84static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
85{
86 kfree(v);
87}
88
89static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
90{
91 struct pstore_private *ps = s->private;
92 struct pstore_ftrace_seq_data *data = v;
93
94 (*pos)++;
95 data->off += REC_SIZE;
96 if (data->off + REC_SIZE > ps->total_size)
97 return NULL;
98
99 return data;
100}
101
102static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
103{
104 struct pstore_private *ps = s->private;
105 struct pstore_ftrace_seq_data *data = v;
106 struct pstore_ftrace_record *rec;
107
108 if (!data)
109 return 0;
110
111 rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
112
113 seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %ps <- %pS\n",
114 pstore_ftrace_decode_cpu(rec),
115 pstore_ftrace_read_timestamp(rec),
116 rec->ip, rec->parent_ip, (void *)rec->ip,
117 (void *)rec->parent_ip);
118
119 return 0;
120}
121
122static const struct seq_operations pstore_ftrace_seq_ops = {
123 .start = pstore_ftrace_seq_start,
124 .next = pstore_ftrace_seq_next,
125 .stop = pstore_ftrace_seq_stop,
126 .show = pstore_ftrace_seq_show,
127};
128
129static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
130 size_t count, loff_t *ppos)
131{
132 struct seq_file *sf = file->private_data;
133 struct pstore_private *ps = sf->private;
134
135 if (ps->record->type == PSTORE_TYPE_FTRACE)
136 return seq_read(file, userbuf, count, ppos);
137 return simple_read_from_buffer(userbuf, count, ppos,
138 ps->record->buf, ps->total_size);
139}
140
141static int pstore_file_open(struct inode *inode, struct file *file)
142{
143 struct pstore_private *ps = inode->i_private;
144 struct seq_file *sf;
145 int err;
146 const struct seq_operations *sops = NULL;
147
148 if (ps->record->type == PSTORE_TYPE_FTRACE)
149 sops = &pstore_ftrace_seq_ops;
150
151 err = seq_open(file, sops);
152 if (err < 0)
153 return err;
154
155 sf = file->private_data;
156 sf->private = ps;
157
158 return 0;
159}
160
161static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
162{
163 struct seq_file *sf = file->private_data;
164
165 if (sf->op)
166 return seq_lseek(file, off, whence);
167 return default_llseek(file, off, whence);
168}
169
170static const struct file_operations pstore_file_operations = {
171 .open = pstore_file_open,
172 .read = pstore_file_read,
173 .llseek = pstore_file_llseek,
174 .release = seq_release,
175};
176
177/*
178 * When a file is unlinked from our file system we call the
179 * platform driver to erase the record from persistent store.
180 */
181static int pstore_unlink(struct inode *dir, struct dentry *dentry)
182{
183 struct pstore_private *p = d_inode(dentry)->i_private;
184 struct pstore_record *record = p->record;
185 int rc = 0;
186
187 if (!record->psi->erase)
188 return -EPERM;
189
190 /* Make sure we can't race while removing this file. */
191 mutex_lock(&records_list_lock);
192 if (!list_empty(&p->list))
193 list_del_init(&p->list);
194 else
195 rc = -ENOENT;
196 p->dentry = NULL;
197 mutex_unlock(&records_list_lock);
198 if (rc)
199 return rc;
200
201 mutex_lock(&record->psi->read_mutex);
202 record->psi->erase(record);
203 mutex_unlock(&record->psi->read_mutex);
204
205 return simple_unlink(dir, dentry);
206}
207
208static void pstore_evict_inode(struct inode *inode)
209{
210 struct pstore_private *p = inode->i_private;
211
212 clear_inode(inode);
213 free_pstore_private(p);
214}
215
216static const struct inode_operations pstore_dir_inode_operations = {
217 .lookup = simple_lookup,
218 .unlink = pstore_unlink,
219};
220
221static struct inode *pstore_get_inode(struct super_block *sb)
222{
223 struct inode *inode = new_inode(sb);
224 if (inode) {
225 inode->i_ino = get_next_ino();
226 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
227 }
228 return inode;
229}
230
231enum {
232 Opt_kmsg_bytes, Opt_err
233};
234
235static const match_table_t tokens = {
236 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
237 {Opt_err, NULL}
238};
239
240static void parse_options(char *options)
241{
242 char *p;
243 substring_t args[MAX_OPT_ARGS];
244 int option;
245
246 if (!options)
247 return;
248
249 while ((p = strsep(&options, ",")) != NULL) {
250 int token;
251
252 if (!*p)
253 continue;
254
255 token = match_token(p, tokens, args);
256 switch (token) {
257 case Opt_kmsg_bytes:
258 if (!match_int(&args[0], &option))
259 pstore_set_kmsg_bytes(option);
260 break;
261 }
262 }
263}
264
265/*
266 * Display the mount options in /proc/mounts.
267 */
268static int pstore_show_options(struct seq_file *m, struct dentry *root)
269{
270 if (kmsg_bytes != CONFIG_PSTORE_DEFAULT_KMSG_BYTES)
271 seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes);
272 return 0;
273}
274
275static int pstore_remount(struct super_block *sb, int *flags, char *data)
276{
277 sync_filesystem(sb);
278 parse_options(data);
279
280 return 0;
281}
282
283static const struct super_operations pstore_ops = {
284 .statfs = simple_statfs,
285 .drop_inode = generic_delete_inode,
286 .evict_inode = pstore_evict_inode,
287 .remount_fs = pstore_remount,
288 .show_options = pstore_show_options,
289};
290
291static struct dentry *psinfo_lock_root(void)
292{
293 struct dentry *root;
294
295 mutex_lock(&pstore_sb_lock);
296 /*
297 * Having no backend is fine -- no records appear.
298 * Not being mounted is fine -- nothing to do.
299 */
300 if (!psinfo || !pstore_sb) {
301 mutex_unlock(&pstore_sb_lock);
302 return NULL;
303 }
304
305 root = pstore_sb->s_root;
306 inode_lock(d_inode(root));
307 mutex_unlock(&pstore_sb_lock);
308
309 return root;
310}
311
312int pstore_put_backend_records(struct pstore_info *psi)
313{
314 struct pstore_private *pos, *tmp;
315 struct dentry *root;
316 int rc = 0;
317
318 root = psinfo_lock_root();
319 if (!root)
320 return 0;
321
322 mutex_lock(&records_list_lock);
323 list_for_each_entry_safe(pos, tmp, &records_list, list) {
324 if (pos->record->psi == psi) {
325 list_del_init(&pos->list);
326 rc = simple_unlink(d_inode(root), pos->dentry);
327 if (WARN_ON(rc))
328 break;
329 d_drop(pos->dentry);
330 dput(pos->dentry);
331 pos->dentry = NULL;
332 }
333 }
334 mutex_unlock(&records_list_lock);
335
336 inode_unlock(d_inode(root));
337
338 return rc;
339}
340
341/*
342 * Make a regular file in the root directory of our file system.
343 * Load it up with "size" bytes of data from "buf".
344 * Set the mtime & ctime to the date that this record was originally stored.
345 */
346int pstore_mkfile(struct dentry *root, struct pstore_record *record)
347{
348 struct dentry *dentry;
349 struct inode *inode;
350 int rc = 0;
351 char name[PSTORE_NAMELEN];
352 struct pstore_private *private, *pos;
353 size_t size = record->size + record->ecc_notice_size;
354
355 if (WARN_ON(!inode_is_locked(d_inode(root))))
356 return -EINVAL;
357
358 rc = -EEXIST;
359 /* Skip records that are already present in the filesystem. */
360 mutex_lock(&records_list_lock);
361 list_for_each_entry(pos, &records_list, list) {
362 if (pos->record->type == record->type &&
363 pos->record->id == record->id &&
364 pos->record->psi == record->psi)
365 goto fail;
366 }
367
368 rc = -ENOMEM;
369 inode = pstore_get_inode(root->d_sb);
370 if (!inode)
371 goto fail;
372 inode->i_mode = S_IFREG | 0444;
373 inode->i_fop = &pstore_file_operations;
374 scnprintf(name, sizeof(name), "%s-%s-%llu%s",
375 pstore_type_to_name(record->type),
376 record->psi->name, record->id,
377 record->compressed ? ".enc.z" : "");
378
379 private = kzalloc(sizeof(*private), GFP_KERNEL);
380 if (!private)
381 goto fail_inode;
382
383 dentry = d_alloc_name(root, name);
384 if (!dentry)
385 goto fail_private;
386
387 private->dentry = dentry;
388 private->record = record;
389 inode->i_size = private->total_size = size;
390 inode->i_private = private;
391
392 if (record->time.tv_sec)
393 inode->i_mtime = inode->i_ctime = record->time;
394
395 d_add(dentry, inode);
396
397 list_add(&private->list, &records_list);
398 mutex_unlock(&records_list_lock);
399
400 return 0;
401
402fail_private:
403 free_pstore_private(private);
404fail_inode:
405 iput(inode);
406fail:
407 mutex_unlock(&records_list_lock);
408 return rc;
409}
410
411/*
412 * Read all the records from the persistent store. Create
413 * files in our filesystem. Don't warn about -EEXIST errors
414 * when we are re-scanning the backing store looking to add new
415 * error records.
416 */
417void pstore_get_records(int quiet)
418{
419 struct dentry *root;
420
421 root = psinfo_lock_root();
422 if (!root)
423 return;
424
425 pstore_get_backend_records(psinfo, root, quiet);
426 inode_unlock(d_inode(root));
427}
428
429static int pstore_fill_super(struct super_block *sb, void *data, int silent)
430{
431 struct inode *inode;
432
433 sb->s_maxbytes = MAX_LFS_FILESIZE;
434 sb->s_blocksize = PAGE_SIZE;
435 sb->s_blocksize_bits = PAGE_SHIFT;
436 sb->s_magic = PSTOREFS_MAGIC;
437 sb->s_op = &pstore_ops;
438 sb->s_time_gran = 1;
439
440 parse_options(data);
441
442 inode = pstore_get_inode(sb);
443 if (inode) {
444 inode->i_mode = S_IFDIR | 0750;
445 inode->i_op = &pstore_dir_inode_operations;
446 inode->i_fop = &simple_dir_operations;
447 inc_nlink(inode);
448 }
449 sb->s_root = d_make_root(inode);
450 if (!sb->s_root)
451 return -ENOMEM;
452
453 mutex_lock(&pstore_sb_lock);
454 pstore_sb = sb;
455 mutex_unlock(&pstore_sb_lock);
456
457 pstore_get_records(0);
458
459 return 0;
460}
461
462static struct dentry *pstore_mount(struct file_system_type *fs_type,
463 int flags, const char *dev_name, void *data)
464{
465 return mount_single(fs_type, flags, data, pstore_fill_super);
466}
467
468static void pstore_kill_sb(struct super_block *sb)
469{
470 mutex_lock(&pstore_sb_lock);
471 WARN_ON(pstore_sb && pstore_sb != sb);
472
473 kill_litter_super(sb);
474 pstore_sb = NULL;
475
476 mutex_lock(&records_list_lock);
477 INIT_LIST_HEAD(&records_list);
478 mutex_unlock(&records_list_lock);
479
480 mutex_unlock(&pstore_sb_lock);
481}
482
483static struct file_system_type pstore_fs_type = {
484 .owner = THIS_MODULE,
485 .name = "pstore",
486 .mount = pstore_mount,
487 .kill_sb = pstore_kill_sb,
488};
489
490int __init pstore_init_fs(void)
491{
492 int err;
493
494 /* Create a convenient mount point for people to access pstore */
495 err = sysfs_create_mount_point(fs_kobj, "pstore");
496 if (err)
497 goto out;
498
499 err = register_filesystem(&pstore_fs_type);
500 if (err < 0)
501 sysfs_remove_mount_point(fs_kobj, "pstore");
502
503out:
504 return err;
505}
506
507void __exit pstore_exit_fs(void)
508{
509 unregister_filesystem(&pstore_fs_type);
510 sysfs_remove_mount_point(fs_kobj, "pstore");
511}