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2024-05-16 8d2a02b24d66aa359e83eebc1ed3c0f85367a1cb 
 kernel/fs/pstore/inode.c
....@@ -1,20 +1,8 @@
1
+// SPDX-License-Identifier: GPL-2.0-only
12 /*
23  * Persistent Storage - ramfs parts.
34  *
45  * 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
186  */
197 
208 #include <linux/module.h>
....@@ -34,7 +22,6 @@
3422 #include <linux/magic.h>
3523 #include <linux/pstore.h>
3624 #include <linux/slab.h>
37
-#include <linux/spinlock.h>
3825 #include <linux/uaccess.h>
3926 
4027 #ifdef CONFIG_PSTORE_BOOT_LOG
....@@ -46,11 +33,15 @@
4633 
4734 #define	PSTORE_NAMELEN	64
4835 
49
-static DEFINE_SPINLOCK(allpstore_lock);
50
-static LIST_HEAD(allpstore);
36
+static DEFINE_MUTEX(records_list_lock);
37
+static LIST_HEAD(records_list);
38
+
39
+static DEFINE_MUTEX(pstore_sb_lock);
40
+static struct super_block *pstore_sb;
5141 
5242 struct pstore_private {
5343 	struct list_head list;
44
+	struct dentry *dentry;
5445 	struct pstore_record *record;
5546 	size_t total_size;
5647 };
....@@ -123,7 +114,7 @@
123114 
124115 	rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
125116 
126
-	seq_printf(s, "CPU:%d ts:%llu %08lx  %08lx  %pf <- %pF\n",
117
+	seq_printf(s, "CPU:%d ts:%llu %08lx  %08lx  %ps <- %pS\n",
127118 		   pstore_ftrace_decode_cpu(rec),
128119 		   pstore_ftrace_read_timestamp(rec),
129120 		   rec->ip, rec->parent_ip, (void *)rec->ip,
....@@ -145,39 +136,13 @@
145136 	struct seq_file *sf = file->private_data;
146137 	struct pstore_private *ps = sf->private;
147138 #ifdef CONFIG_PSTORE_BOOT_LOG
139
+	size_t size = 0;
148140 	struct pstore_record *record = ps->record;
149
-	struct ramoops_context *cxt = record->psi->data;
150
-	struct persistent_ram_zone *prz;
151
-	struct persistent_ram_buffer *buffer;
152
-	char *log_tmp;
153
-	size_t size, start, n;
154141 
155
-	if (ps->record->type == PSTORE_TYPE_BOOT_LOG) {
156
-
157
-		if (!cxt)
158
-			return count;
159
-
160
-		prz = cxt->boot_przs[record->id];
161
-
162
-		if (!prz)
163
-			return count;
164
-
165
-		buffer = prz->buffer;
166
-		if (!buffer)
167
-			return count;
168
-
169
-		size = atomic_read(&buffer->size);
170
-		start = atomic_read(&buffer->start);
171
-
172
-		log_tmp = kmalloc(size, GFP_KERNEL);
173
-		if (!log_tmp)
174
-			return count;
175
-		memcpy_fromio(log_tmp, &buffer->data[start], size - start);
176
-		memcpy_fromio(log_tmp + size - start, &buffer->data[0], start);
177
-
178
-		n = simple_read_from_buffer(userbuf, count, ppos, log_tmp, size);
179
-		kfree(log_tmp);
180
-		return n;
142
+	if (record->type == PSTORE_TYPE_BOOT_LOG) {
143
+		size = ramoops_pstore_read_for_boot_log(ps->record);
144
+		size = simple_read_from_buffer(userbuf, count, ppos, record->buf, size);
145
+		return size;
181146 	}
182147 #endif
183148 	if (ps->record->type == PSTORE_TYPE_FTRACE)
....@@ -230,9 +195,21 @@
230195 {
231196 	struct pstore_private *p = d_inode(dentry)->i_private;
232197 	struct pstore_record *record = p->record;
198
+	int rc = 0;
233199 
234200 	if (!record->psi->erase)
235201 		return -EPERM;
202
+
203
+	/* Make sure we can't race while removing this file. */
204
+	mutex_lock(&records_list_lock);
205
+	if (!list_empty(&p->list))
206
+		list_del_init(&p->list);
207
+	else
208
+		rc = -ENOENT;
209
+	p->dentry = NULL;
210
+	mutex_unlock(&records_list_lock);
211
+	if (rc)
212
+		return rc;
236213 
237214 	mutex_lock(&record->psi->read_mutex);
238215 	record->psi->erase(record);
....@@ -244,15 +221,9 @@
244221 static void pstore_evict_inode(struct inode *inode)
245222 {
246223 	struct pstore_private	*p = inode->i_private;
247
-	unsigned long		flags;
248224 
249225 	clear_inode(inode);
250
-	if (p) {
251
-		spin_lock_irqsave(&allpstore_lock, flags);
252
-		list_del(&p->list);
253
-		spin_unlock_irqrestore(&allpstore_lock, flags);
254
-		free_pstore_private(p);
255
-	}
226
+	free_pstore_private(p);
256227 }
257228 
258229 static const struct inode_operations pstore_dir_inode_operations = {
....@@ -330,11 +301,54 @@
330301 	.show_options	= pstore_show_options,
331302 };
332303 
333
-static struct super_block *pstore_sb;
334
-
335
-bool pstore_is_mounted(void)
304
+static struct dentry *psinfo_lock_root(void)
336305 {
337
-	return pstore_sb != NULL;
306
+	struct dentry *root;
307
+
308
+	mutex_lock(&pstore_sb_lock);
309
+	/*
310
+	 * Having no backend is fine -- no records appear.
311
+	 * Not being mounted is fine -- nothing to do.
312
+	 */
313
+	if (!psinfo || !pstore_sb) {
314
+		mutex_unlock(&pstore_sb_lock);
315
+		return NULL;
316
+	}
317
+
318
+	root = pstore_sb->s_root;
319
+	inode_lock(d_inode(root));
320
+	mutex_unlock(&pstore_sb_lock);
321
+
322
+	return root;
323
+}
324
+
325
+int pstore_put_backend_records(struct pstore_info *psi)
326
+{
327
+	struct pstore_private *pos, *tmp;
328
+	struct dentry *root;
329
+	int rc = 0;
330
+
331
+	root = psinfo_lock_root();
332
+	if (!root)
333
+		return 0;
334
+
335
+	mutex_lock(&records_list_lock);
336
+	list_for_each_entry_safe(pos, tmp, &records_list, list) {
337
+		if (pos->record->psi == psi) {
338
+			list_del_init(&pos->list);
339
+			rc = simple_unlink(d_inode(root), pos->dentry);
340
+			if (WARN_ON(rc))
341
+				break;
342
+			d_drop(pos->dentry);
343
+			dput(pos->dentry);
344
+			pos->dentry = NULL;
345
+		}
346
+	}
347
+	mutex_unlock(&records_list_lock);
348
+
349
+	inode_unlock(d_inode(root));
350
+
351
+	return rc;
338352 }
339353 
340354 /*
....@@ -349,23 +363,20 @@
349363 	int			rc = 0;
350364 	char			name[PSTORE_NAMELEN];
351365 	struct pstore_private	*private, *pos;
352
-	unsigned long		flags;
353366 	size_t			size = record->size + record->ecc_notice_size;
354367 
355
-	WARN_ON(!inode_is_locked(d_inode(root)));
368
+	if (WARN_ON(!inode_is_locked(d_inode(root))))
369
+		return -EINVAL;
356370 
357
-	spin_lock_irqsave(&allpstore_lock, flags);
358
-	list_for_each_entry(pos, &allpstore, list) {
371
+	rc = -EEXIST;
372
+	/* Skip records that are already present in the filesystem. */
373
+	mutex_lock(&records_list_lock);
374
+	list_for_each_entry(pos, &records_list, list) {
359375 		if (pos->record->type == record->type &&
360376 		    pos->record->id == record->id &&
361
-		    pos->record->psi == record->psi) {
362
-			rc = -EEXIST;
363
-			break;
364
-		}
377
+		    pos->record->psi == record->psi)
378
+			goto fail;
365379 	}
366
-	spin_unlock_irqrestore(&allpstore_lock, flags);
367
-	if (rc)
368
-		return rc;
369380 
370381 	rc = -ENOMEM;
371382 	inode = pstore_get_inode(root->d_sb);
....@@ -373,59 +384,10 @@
373384 		goto fail;
374385 	inode->i_mode = S_IFREG | 0444;
375386 	inode->i_fop = &pstore_file_operations;
376
-
377
-	switch (record->type) {
378
-	case PSTORE_TYPE_DMESG:
379
-		scnprintf(name, sizeof(name), "dmesg-%s-%llu%s",
380
-			  record->psi->name, record->id,
381
-			  record->compressed ? ".enc.z" : "");
382
-		break;
383
-	case PSTORE_TYPE_CONSOLE:
384
-		scnprintf(name, sizeof(name), "console-%s-%llu",
385
-			  record->psi->name, record->id);
386
-		break;
387
-	case PSTORE_TYPE_FTRACE:
388
-		scnprintf(name, sizeof(name), "ftrace-%s-%llu",
389
-			  record->psi->name, record->id);
390
-		break;
391
-	case PSTORE_TYPE_MCE:
392
-		scnprintf(name, sizeof(name), "mce-%s-%llu",
393
-			  record->psi->name, record->id);
394
-		break;
395
-	case PSTORE_TYPE_PPC_RTAS:
396
-		scnprintf(name, sizeof(name), "rtas-%s-%llu",
397
-			  record->psi->name, record->id);
398
-		break;
399
-	case PSTORE_TYPE_PPC_OF:
400
-		scnprintf(name, sizeof(name), "powerpc-ofw-%s-%llu",
401
-			  record->psi->name, record->id);
402
-		break;
403
-	case PSTORE_TYPE_PPC_COMMON:
404
-		scnprintf(name, sizeof(name), "powerpc-common-%s-%llu",
405
-			  record->psi->name, record->id);
406
-		break;
407
-	case PSTORE_TYPE_PMSG:
408
-		scnprintf(name, sizeof(name), "pmsg-%s-%llu",
409
-			  record->psi->name, record->id);
410
-		break;
411
-	case PSTORE_TYPE_PPC_OPAL:
412
-		scnprintf(name, sizeof(name), "powerpc-opal-%s-%llu",
413
-			  record->psi->name, record->id);
414
-		break;
415
-#ifdef CONFIG_PSTORE_BOOT_LOG
416
-	case PSTORE_TYPE_BOOT_LOG:
417
-		scnprintf(name, sizeof(name), "boot-log-%llu", record->id);
418
-		break;
419
-#endif
420
-	case PSTORE_TYPE_UNKNOWN:
421
-		scnprintf(name, sizeof(name), "unknown-%s-%llu",
422
-			  record->psi->name, record->id);
423
-		break;
424
-	default:
425
-		scnprintf(name, sizeof(name), "type%d-%s-%llu",
426
-			  record->type, record->psi->name, record->id);
427
-		break;
428
-	}
387
+	scnprintf(name, sizeof(name), "%s-%s-%llu%s",
388
+			pstore_type_to_name(record->type),
389
+			record->psi->name, record->id,
390
+			record->compressed ? ".enc.z" : "");
429391 
430392 	private = kzalloc(sizeof(*private), GFP_KERNEL);
431393 	if (!private)
....@@ -435,6 +397,7 @@
435397 	if (!dentry)
436398 		goto fail_private;
437399 
400
+	private->dentry = dentry;
438401 	private->record = record;
439402 	inode->i_size = private->total_size = size;
440403 	inode->i_private = private;
....@@ -444,9 +407,8 @@
444407 
445408 	d_add(dentry, inode);
446409 
447
-	spin_lock_irqsave(&allpstore_lock, flags);
448
-	list_add(&private->list, &allpstore);
449
-	spin_unlock_irqrestore(&allpstore_lock, flags);
410
+	list_add(&private->list, &records_list);
411
+	mutex_unlock(&records_list_lock);
450412 
451413 	return 0;
452414 
....@@ -454,8 +416,8 @@
454416 	free_pstore_private(private);
455417 fail_inode:
456418 	iput(inode);
457
-
458419 fail:
420
+	mutex_unlock(&records_list_lock);
459421 	return rc;
460422 }
461423 
....@@ -467,24 +429,19 @@
467429  */
468430 void pstore_get_records(int quiet)
469431 {
470
-	struct pstore_info *psi = psinfo;
471432 	struct dentry *root;
472433 
473
-	if (!psi || !pstore_sb)
434
+	root = psinfo_lock_root();
435
+	if (!root)
474436 		return;
475437 
476
-	root = pstore_sb->s_root;
477
-
478
-	inode_lock(d_inode(root));
479
-	pstore_get_backend_records(psi, root, quiet);
438
+	pstore_get_backend_records(psinfo, root, quiet);
480439 	inode_unlock(d_inode(root));
481440 }
482441 
483442 static int pstore_fill_super(struct super_block *sb, void *data, int silent)
484443 {
485444 	struct inode *inode;
486
-
487
-	pstore_sb = sb;
488445 
489446 	sb->s_maxbytes		= MAX_LFS_FILESIZE;
490447 	sb->s_blocksize		= PAGE_SIZE;
....@@ -506,6 +463,10 @@
506463 	if (!sb->s_root)
507464 		return -ENOMEM;
508465 
466
+	mutex_lock(&pstore_sb_lock);
467
+	pstore_sb = sb;
468
+	mutex_unlock(&pstore_sb_lock);
469
+
509470 	pstore_get_records(0);
510471 
511472 	return 0;
....@@ -519,8 +480,17 @@
519480 
520481 static void pstore_kill_sb(struct super_block *sb)
521482 {
483
+	mutex_lock(&pstore_sb_lock);
484
+	WARN_ON(pstore_sb && pstore_sb != sb);
485
+
522486 	kill_litter_super(sb);
523487 	pstore_sb = NULL;
488
+
489
+	mutex_lock(&records_list_lock);
490
+	INIT_LIST_HEAD(&records_list);
491
+	mutex_unlock(&records_list_lock);
492
+
493
+	mutex_unlock(&pstore_sb_lock);
524494 }
525495 
526496 static struct file_system_type pstore_fs_type = {