1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * linux/fs/jbd2/journal.c
4  *
5  * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
6  *
7  * Copyright 1998 Red Hat corp --- All Rights Reserved
8  *
9  * Generic filesystem journal-writing code; part of the ext2fs
10  * journaling system.
11  *
12  * This file manages journals: areas of disk reserved for logging
13  * transactional updates.  This includes the kernel journaling thread
14  * which is responsible for scheduling updates to the log.
15  *
16  * We do not actually manage the physical storage of the journal in this
17  * file: that is left to a per-journal policy function, which allows us
18  * to store the journal within a filesystem-specified area for ext2
19  * journaling (ext2 can use a reserved inode for storing the log).
20  */
21 
22 #include <linux/module.h>
23 #include <linux/time.h>
24 #include <linux/fs.h>
25 #include <linux/jbd2.h>
26 #include <linux/errno.h>
27 #include <linux/slab.h>
28 #include <linux/init.h>
29 #include <linux/mm.h>
30 #include <linux/freezer.h>
31 #include <linux/pagemap.h>
32 #include <linux/kthread.h>
33 #include <linux/poison.h>
34 #include <linux/proc_fs.h>
35 #include <linux/seq_file.h>
36 #include <linux/math64.h>
37 #include <linux/hash.h>
38 #include <linux/log2.h>
39 #include <linux/vmalloc.h>
40 #include <linux/backing-dev.h>
41 #include <linux/bitops.h>
42 #include <linux/ratelimit.h>
43 #include <linux/sched/mm.h>
44 
45 #define CREATE_TRACE_POINTS
46 #include <trace/events/jbd2.h>
47 
48 #include <linux/uaccess.h>
49 #include <asm/page.h>
50 
51 #ifdef CONFIG_JBD2_DEBUG
52 ushort jbd2_journal_enable_debug __read_mostly;
53 EXPORT_SYMBOL(jbd2_journal_enable_debug);
54 
55 module_param_named(jbd2_debug, jbd2_journal_enable_debug, ushort, 0644);
56 MODULE_PARM_DESC(jbd2_debug, "Debugging level for jbd2");
57 #endif
58 
59 EXPORT_SYMBOL(jbd2_journal_extend);
60 EXPORT_SYMBOL(jbd2_journal_stop);
61 EXPORT_SYMBOL(jbd2_journal_lock_updates);
62 EXPORT_SYMBOL(jbd2_journal_unlock_updates);
63 EXPORT_SYMBOL(jbd2_journal_get_write_access);
64 EXPORT_SYMBOL(jbd2_journal_get_create_access);
65 EXPORT_SYMBOL(jbd2_journal_get_undo_access);
66 EXPORT_SYMBOL(jbd2_journal_set_triggers);
67 EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
68 EXPORT_SYMBOL(jbd2_journal_forget);
69 EXPORT_SYMBOL(jbd2_journal_flush);
70 EXPORT_SYMBOL(jbd2_journal_revoke);
71 
72 EXPORT_SYMBOL(jbd2_journal_init_dev);
73 EXPORT_SYMBOL(jbd2_journal_init_inode);
74 EXPORT_SYMBOL(jbd2_journal_check_used_features);
75 EXPORT_SYMBOL(jbd2_journal_check_available_features);
76 EXPORT_SYMBOL(jbd2_journal_set_features);
77 EXPORT_SYMBOL(jbd2_journal_load);
78 EXPORT_SYMBOL(jbd2_journal_destroy);
79 EXPORT_SYMBOL(jbd2_journal_abort);
80 EXPORT_SYMBOL(jbd2_journal_errno);
81 EXPORT_SYMBOL(jbd2_journal_ack_err);
82 EXPORT_SYMBOL(jbd2_journal_clear_err);
83 EXPORT_SYMBOL(jbd2_log_wait_commit);
84 EXPORT_SYMBOL(jbd2_log_start_commit);
85 EXPORT_SYMBOL(jbd2_journal_start_commit);
86 EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
87 EXPORT_SYMBOL(jbd2_journal_wipe);
88 EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
89 EXPORT_SYMBOL(jbd2_journal_invalidate_folio);
90 EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
91 EXPORT_SYMBOL(jbd2_journal_force_commit);
92 EXPORT_SYMBOL(jbd2_journal_inode_ranged_write);
93 EXPORT_SYMBOL(jbd2_journal_inode_ranged_wait);
94 EXPORT_SYMBOL(jbd2_journal_submit_inode_data_buffers);
95 EXPORT_SYMBOL(jbd2_journal_finish_inode_data_buffers);
96 EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
97 EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
98 EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
99 EXPORT_SYMBOL(jbd2_inode_cache);
100 
101 static int jbd2_journal_create_slab(size_t slab_size);
102 
103 #ifdef CONFIG_JBD2_DEBUG
__jbd2_debug(int level,const char * file,const char * func,unsigned int line,const char * fmt,...)104 void __jbd2_debug(int level, const char *file, const char *func,
105 		  unsigned int line, const char *fmt, ...)
106 {
107 	struct va_format vaf;
108 	va_list args;
109 
110 	if (level > jbd2_journal_enable_debug)
111 		return;
112 	va_start(args, fmt);
113 	vaf.fmt = fmt;
114 	vaf.va = &args;
115 	printk(KERN_DEBUG "%s: (%s, %u): %pV", file, func, line, &vaf);
116 	va_end(args);
117 }
118 EXPORT_SYMBOL(__jbd2_debug);
119 #endif
120 
121 /* Checksumming functions */
jbd2_verify_csum_type(journal_t * j,journal_superblock_t * sb)122 static int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
123 {
124 	if (!jbd2_journal_has_csum_v2or3_feature(j))
125 		return 1;
126 
127 	return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
128 }
129 
jbd2_superblock_csum(journal_t * j,journal_superblock_t * sb)130 static __be32 jbd2_superblock_csum(journal_t *j, journal_superblock_t *sb)
131 {
132 	__u32 csum;
133 	__be32 old_csum;
134 
135 	old_csum = sb->s_checksum;
136 	sb->s_checksum = 0;
137 	csum = jbd2_chksum(j, ~0, (char *)sb, sizeof(journal_superblock_t));
138 	sb->s_checksum = old_csum;
139 
140 	return cpu_to_be32(csum);
141 }
142 
143 /*
144  * Helper function used to manage commit timeouts
145  */
146 
commit_timeout(struct timer_list * t)147 static void commit_timeout(struct timer_list *t)
148 {
149 	journal_t *journal = from_timer(journal, t, j_commit_timer);
150 
151 	wake_up_process(journal->j_task);
152 }
153 
154 /*
155  * kjournald2: The main thread function used to manage a logging device
156  * journal.
157  *
158  * This kernel thread is responsible for two things:
159  *
160  * 1) COMMIT:  Every so often we need to commit the current state of the
161  *    filesystem to disk.  The journal thread is responsible for writing
162  *    all of the metadata buffers to disk. If a fast commit is ongoing
163  *    journal thread waits until it's done and then continues from
164  *    there on.
165  *
166  * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
167  *    of the data in that part of the log has been rewritten elsewhere on
168  *    the disk.  Flushing these old buffers to reclaim space in the log is
169  *    known as checkpointing, and this thread is responsible for that job.
170  */
171 
kjournald2(void * arg)172 static int kjournald2(void *arg)
173 {
174 	journal_t *journal = arg;
175 	transaction_t *transaction;
176 
177 	/*
178 	 * Set up an interval timer which can be used to trigger a commit wakeup
179 	 * after the commit interval expires
180 	 */
181 	timer_setup(&journal->j_commit_timer, commit_timeout, 0);
182 
183 	set_freezable();
184 
185 	/* Record that the journal thread is running */
186 	journal->j_task = current;
187 	wake_up(&journal->j_wait_done_commit);
188 
189 	/*
190 	 * Make sure that no allocations from this kernel thread will ever
191 	 * recurse to the fs layer because we are responsible for the
192 	 * transaction commit and any fs involvement might get stuck waiting for
193 	 * the trasn. commit.
194 	 */
195 	memalloc_nofs_save();
196 
197 	/*
198 	 * And now, wait forever for commit wakeup events.
199 	 */
200 	write_lock(&journal->j_state_lock);
201 
202 loop:
203 	if (journal->j_flags & JBD2_UNMOUNT)
204 		goto end_loop;
205 
206 	jbd_debug(1, "commit_sequence=%u, commit_request=%u\n",
207 		journal->j_commit_sequence, journal->j_commit_request);
208 
209 	if (journal->j_commit_sequence != journal->j_commit_request) {
210 		jbd_debug(1, "OK, requests differ\n");
211 		write_unlock(&journal->j_state_lock);
212 		del_timer_sync(&journal->j_commit_timer);
213 		jbd2_journal_commit_transaction(journal);
214 		write_lock(&journal->j_state_lock);
215 		goto loop;
216 	}
217 
218 	wake_up(&journal->j_wait_done_commit);
219 	if (freezing(current)) {
220 		/*
221 		 * The simpler the better. Flushing journal isn't a
222 		 * good idea, because that depends on threads that may
223 		 * be already stopped.
224 		 */
225 		jbd_debug(1, "Now suspending kjournald2\n");
226 		write_unlock(&journal->j_state_lock);
227 		try_to_freeze();
228 		write_lock(&journal->j_state_lock);
229 	} else {
230 		/*
231 		 * We assume on resume that commits are already there,
232 		 * so we don't sleep
233 		 */
234 		DEFINE_WAIT(wait);
235 		int should_sleep = 1;
236 
237 		prepare_to_wait(&journal->j_wait_commit, &wait,
238 				TASK_INTERRUPTIBLE);
239 		if (journal->j_commit_sequence != journal->j_commit_request)
240 			should_sleep = 0;
241 		transaction = journal->j_running_transaction;
242 		if (transaction && time_after_eq(jiffies,
243 						transaction->t_expires))
244 			should_sleep = 0;
245 		if (journal->j_flags & JBD2_UNMOUNT)
246 			should_sleep = 0;
247 		if (should_sleep) {
248 			write_unlock(&journal->j_state_lock);
249 			schedule();
250 			write_lock(&journal->j_state_lock);
251 		}
252 		finish_wait(&journal->j_wait_commit, &wait);
253 	}
254 
255 	jbd_debug(1, "kjournald2 wakes\n");
256 
257 	/*
258 	 * Were we woken up by a commit wakeup event?
259 	 */
260 	transaction = journal->j_running_transaction;
261 	if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
262 		journal->j_commit_request = transaction->t_tid;
263 		jbd_debug(1, "woke because of timeout\n");
264 	}
265 	goto loop;
266 
267 end_loop:
268 	del_timer_sync(&journal->j_commit_timer);
269 	journal->j_task = NULL;
270 	wake_up(&journal->j_wait_done_commit);
271 	jbd_debug(1, "Journal thread exiting.\n");
272 	write_unlock(&journal->j_state_lock);
273 	return 0;
274 }
275 
jbd2_journal_start_thread(journal_t * journal)276 static int jbd2_journal_start_thread(journal_t *journal)
277 {
278 	struct task_struct *t;
279 
280 	t = kthread_run(kjournald2, journal, "jbd2/%s",
281 			journal->j_devname);
282 	if (IS_ERR(t))
283 		return PTR_ERR(t);
284 
285 	wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
286 	return 0;
287 }
288 
journal_kill_thread(journal_t * journal)289 static void journal_kill_thread(journal_t *journal)
290 {
291 	write_lock(&journal->j_state_lock);
292 	journal->j_flags |= JBD2_UNMOUNT;
293 
294 	while (journal->j_task) {
295 		write_unlock(&journal->j_state_lock);
296 		wake_up(&journal->j_wait_commit);
297 		wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
298 		write_lock(&journal->j_state_lock);
299 	}
300 	write_unlock(&journal->j_state_lock);
301 }
302 
303 /*
304  * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
305  *
306  * Writes a metadata buffer to a given disk block.  The actual IO is not
307  * performed but a new buffer_head is constructed which labels the data
308  * to be written with the correct destination disk block.
309  *
310  * Any magic-number escaping which needs to be done will cause a
311  * copy-out here.  If the buffer happens to start with the
312  * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
313  * magic number is only written to the log for descripter blocks.  In
314  * this case, we copy the data and replace the first word with 0, and we
315  * return a result code which indicates that this buffer needs to be
316  * marked as an escaped buffer in the corresponding log descriptor
317  * block.  The missing word can then be restored when the block is read
318  * during recovery.
319  *
320  * If the source buffer has already been modified by a new transaction
321  * since we took the last commit snapshot, we use the frozen copy of
322  * that data for IO. If we end up using the existing buffer_head's data
323  * for the write, then we have to make sure nobody modifies it while the
324  * IO is in progress. do_get_write_access() handles this.
325  *
326  * The function returns a pointer to the buffer_head to be used for IO.
327  *
328  *
329  * Return value:
330  *  <0: Error
331  * >=0: Finished OK
332  *
333  * On success:
334  * Bit 0 set == escape performed on the data
335  * Bit 1 set == buffer copy-out performed (kfree the data after IO)
336  */
337 
jbd2_journal_write_metadata_buffer(transaction_t * transaction,struct journal_head * jh_in,struct buffer_head ** bh_out,sector_t blocknr)338 int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
339 				  struct journal_head  *jh_in,
340 				  struct buffer_head **bh_out,
341 				  sector_t blocknr)
342 {
343 	int need_copy_out = 0;
344 	int done_copy_out = 0;
345 	int do_escape = 0;
346 	char *mapped_data;
347 	struct buffer_head *new_bh;
348 	struct page *new_page;
349 	unsigned int new_offset;
350 	struct buffer_head *bh_in = jh2bh(jh_in);
351 	journal_t *journal = transaction->t_journal;
352 
353 	/*
354 	 * The buffer really shouldn't be locked: only the current committing
355 	 * transaction is allowed to write it, so nobody else is allowed
356 	 * to do any IO.
357 	 *
358 	 * akpm: except if we're journalling data, and write() output is
359 	 * also part of a shared mapping, and another thread has
360 	 * decided to launch a writepage() against this buffer.
361 	 */
362 	J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
363 
364 	new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
365 
366 	/* keep subsequent assertions sane */
367 	atomic_set(&new_bh->b_count, 1);
368 
369 	spin_lock(&jh_in->b_state_lock);
370 repeat:
371 	/*
372 	 * If a new transaction has already done a buffer copy-out, then
373 	 * we use that version of the data for the commit.
374 	 */
375 	if (jh_in->b_frozen_data) {
376 		done_copy_out = 1;
377 		new_page = virt_to_page(jh_in->b_frozen_data);
378 		new_offset = offset_in_page(jh_in->b_frozen_data);
379 	} else {
380 		new_page = jh2bh(jh_in)->b_page;
381 		new_offset = offset_in_page(jh2bh(jh_in)->b_data);
382 	}
383 
384 	mapped_data = kmap_atomic(new_page);
385 	/*
386 	 * Fire data frozen trigger if data already wasn't frozen.  Do this
387 	 * before checking for escaping, as the trigger may modify the magic
388 	 * offset.  If a copy-out happens afterwards, it will have the correct
389 	 * data in the buffer.
390 	 */
391 	if (!done_copy_out)
392 		jbd2_buffer_frozen_trigger(jh_in, mapped_data + new_offset,
393 					   jh_in->b_triggers);
394 
395 	/*
396 	 * Check for escaping
397 	 */
398 	if (*((__be32 *)(mapped_data + new_offset)) ==
399 				cpu_to_be32(JBD2_MAGIC_NUMBER)) {
400 		need_copy_out = 1;
401 		do_escape = 1;
402 	}
403 	kunmap_atomic(mapped_data);
404 
405 	/*
406 	 * Do we need to do a data copy?
407 	 */
408 	if (need_copy_out && !done_copy_out) {
409 		char *tmp;
410 
411 		spin_unlock(&jh_in->b_state_lock);
412 		tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
413 		if (!tmp) {
414 			brelse(new_bh);
415 			return -ENOMEM;
416 		}
417 		spin_lock(&jh_in->b_state_lock);
418 		if (jh_in->b_frozen_data) {
419 			jbd2_free(tmp, bh_in->b_size);
420 			goto repeat;
421 		}
422 
423 		jh_in->b_frozen_data = tmp;
424 		mapped_data = kmap_atomic(new_page);
425 		memcpy(tmp, mapped_data + new_offset, bh_in->b_size);
426 		kunmap_atomic(mapped_data);
427 
428 		new_page = virt_to_page(tmp);
429 		new_offset = offset_in_page(tmp);
430 		done_copy_out = 1;
431 
432 		/*
433 		 * This isn't strictly necessary, as we're using frozen
434 		 * data for the escaping, but it keeps consistency with
435 		 * b_frozen_data usage.
436 		 */
437 		jh_in->b_frozen_triggers = jh_in->b_triggers;
438 	}
439 
440 	/*
441 	 * Did we need to do an escaping?  Now we've done all the
442 	 * copying, we can finally do so.
443 	 */
444 	if (do_escape) {
445 		mapped_data = kmap_atomic(new_page);
446 		*((unsigned int *)(mapped_data + new_offset)) = 0;
447 		kunmap_atomic(mapped_data);
448 	}
449 
450 	set_bh_page(new_bh, new_page, new_offset);
451 	new_bh->b_size = bh_in->b_size;
452 	new_bh->b_bdev = journal->j_dev;
453 	new_bh->b_blocknr = blocknr;
454 	new_bh->b_private = bh_in;
455 	set_buffer_mapped(new_bh);
456 	set_buffer_dirty(new_bh);
457 
458 	*bh_out = new_bh;
459 
460 	/*
461 	 * The to-be-written buffer needs to get moved to the io queue,
462 	 * and the original buffer whose contents we are shadowing or
463 	 * copying is moved to the transaction's shadow queue.
464 	 */
465 	JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
466 	spin_lock(&journal->j_list_lock);
467 	__jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
468 	spin_unlock(&journal->j_list_lock);
469 	set_buffer_shadow(bh_in);
470 	spin_unlock(&jh_in->b_state_lock);
471 
472 	return do_escape | (done_copy_out << 1);
473 }
474 
475 /*
476  * Allocation code for the journal file.  Manage the space left in the
477  * journal, so that we can begin checkpointing when appropriate.
478  */
479 
480 /*
481  * Called with j_state_lock locked for writing.
482  * Returns true if a transaction commit was started.
483  */
__jbd2_log_start_commit(journal_t * journal,tid_t target)484 int __jbd2_log_start_commit(journal_t *journal, tid_t target)
485 {
486 	/* Return if the txn has already requested to be committed */
487 	if (journal->j_commit_request == target)
488 		return 0;
489 
490 	/*
491 	 * The only transaction we can possibly wait upon is the
492 	 * currently running transaction (if it exists).  Otherwise,
493 	 * the target tid must be an old one.
494 	 */
495 	if (journal->j_running_transaction &&
496 	    journal->j_running_transaction->t_tid == target) {
497 		/*
498 		 * We want a new commit: OK, mark the request and wakeup the
499 		 * commit thread.  We do _not_ do the commit ourselves.
500 		 */
501 
502 		journal->j_commit_request = target;
503 		jbd_debug(1, "JBD2: requesting commit %u/%u\n",
504 			  journal->j_commit_request,
505 			  journal->j_commit_sequence);
506 		journal->j_running_transaction->t_requested = jiffies;
507 		wake_up(&journal->j_wait_commit);
508 		return 1;
509 	} else if (!tid_geq(journal->j_commit_request, target))
510 		/* This should never happen, but if it does, preserve
511 		   the evidence before kjournald goes into a loop and
512 		   increments j_commit_sequence beyond all recognition. */
513 		WARN_ONCE(1, "JBD2: bad log_start_commit: %u %u %u %u\n",
514 			  journal->j_commit_request,
515 			  journal->j_commit_sequence,
516 			  target, journal->j_running_transaction ?
517 			  journal->j_running_transaction->t_tid : 0);
518 	return 0;
519 }
520 
jbd2_log_start_commit(journal_t * journal,tid_t tid)521 int jbd2_log_start_commit(journal_t *journal, tid_t tid)
522 {
523 	int ret;
524 
525 	write_lock(&journal->j_state_lock);
526 	ret = __jbd2_log_start_commit(journal, tid);
527 	write_unlock(&journal->j_state_lock);
528 	return ret;
529 }
530 
531 /*
532  * Force and wait any uncommitted transactions.  We can only force the running
533  * transaction if we don't have an active handle, otherwise, we will deadlock.
534  * Returns: <0 in case of error,
535  *           0 if nothing to commit,
536  *           1 if transaction was successfully committed.
537  */
__jbd2_journal_force_commit(journal_t * journal)538 static int __jbd2_journal_force_commit(journal_t *journal)
539 {
540 	transaction_t *transaction = NULL;
541 	tid_t tid;
542 	int need_to_start = 0, ret = 0;
543 
544 	read_lock(&journal->j_state_lock);
545 	if (journal->j_running_transaction && !current->journal_info) {
546 		transaction = journal->j_running_transaction;
547 		if (!tid_geq(journal->j_commit_request, transaction->t_tid))
548 			need_to_start = 1;
549 	} else if (journal->j_committing_transaction)
550 		transaction = journal->j_committing_transaction;
551 
552 	if (!transaction) {
553 		/* Nothing to commit */
554 		read_unlock(&journal->j_state_lock);
555 		return 0;
556 	}
557 	tid = transaction->t_tid;
558 	read_unlock(&journal->j_state_lock);
559 	if (need_to_start)
560 		jbd2_log_start_commit(journal, tid);
561 	ret = jbd2_log_wait_commit(journal, tid);
562 	if (!ret)
563 		ret = 1;
564 
565 	return ret;
566 }
567 
568 /**
569  * jbd2_journal_force_commit_nested - Force and wait upon a commit if the
570  * calling process is not within transaction.
571  *
572  * @journal: journal to force
573  * Returns true if progress was made.
574  *
575  * This is used for forcing out undo-protected data which contains
576  * bitmaps, when the fs is running out of space.
577  */
jbd2_journal_force_commit_nested(journal_t * journal)578 int jbd2_journal_force_commit_nested(journal_t *journal)
579 {
580 	int ret;
581 
582 	ret = __jbd2_journal_force_commit(journal);
583 	return ret > 0;
584 }
585 
586 /**
587  * jbd2_journal_force_commit() - force any uncommitted transactions
588  * @journal: journal to force
589  *
590  * Caller want unconditional commit. We can only force the running transaction
591  * if we don't have an active handle, otherwise, we will deadlock.
592  */
jbd2_journal_force_commit(journal_t * journal)593 int jbd2_journal_force_commit(journal_t *journal)
594 {
595 	int ret;
596 
597 	J_ASSERT(!current->journal_info);
598 	ret = __jbd2_journal_force_commit(journal);
599 	if (ret > 0)
600 		ret = 0;
601 	return ret;
602 }
603 
604 /*
605  * Start a commit of the current running transaction (if any).  Returns true
606  * if a transaction is going to be committed (or is currently already
607  * committing), and fills its tid in at *ptid
608  */
jbd2_journal_start_commit(journal_t * journal,tid_t * ptid)609 int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
610 {
611 	int ret = 0;
612 
613 	write_lock(&journal->j_state_lock);
614 	if (journal->j_running_transaction) {
615 		tid_t tid = journal->j_running_transaction->t_tid;
616 
617 		__jbd2_log_start_commit(journal, tid);
618 		/* There's a running transaction and we've just made sure
619 		 * it's commit has been scheduled. */
620 		if (ptid)
621 			*ptid = tid;
622 		ret = 1;
623 	} else if (journal->j_committing_transaction) {
624 		/*
625 		 * If commit has been started, then we have to wait for
626 		 * completion of that transaction.
627 		 */
628 		if (ptid)
629 			*ptid = journal->j_committing_transaction->t_tid;
630 		ret = 1;
631 	}
632 	write_unlock(&journal->j_state_lock);
633 	return ret;
634 }
635 
636 /*
637  * Return 1 if a given transaction has not yet sent barrier request
638  * connected with a transaction commit. If 0 is returned, transaction
639  * may or may not have sent the barrier. Used to avoid sending barrier
640  * twice in common cases.
641  */
jbd2_trans_will_send_data_barrier(journal_t * journal,tid_t tid)642 int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid)
643 {
644 	int ret = 0;
645 	transaction_t *commit_trans;
646 
647 	if (!(journal->j_flags & JBD2_BARRIER))
648 		return 0;
649 	read_lock(&journal->j_state_lock);
650 	/* Transaction already committed? */
651 	if (tid_geq(journal->j_commit_sequence, tid))
652 		goto out;
653 	commit_trans = journal->j_committing_transaction;
654 	if (!commit_trans || commit_trans->t_tid != tid) {
655 		ret = 1;
656 		goto out;
657 	}
658 	/*
659 	 * Transaction is being committed and we already proceeded to
660 	 * submitting a flush to fs partition?
661 	 */
662 	if (journal->j_fs_dev != journal->j_dev) {
663 		if (!commit_trans->t_need_data_flush ||
664 		    commit_trans->t_state >= T_COMMIT_DFLUSH)
665 			goto out;
666 	} else {
667 		if (commit_trans->t_state >= T_COMMIT_JFLUSH)
668 			goto out;
669 	}
670 	ret = 1;
671 out:
672 	read_unlock(&journal->j_state_lock);
673 	return ret;
674 }
675 EXPORT_SYMBOL(jbd2_trans_will_send_data_barrier);
676 
677 /*
678  * Wait for a specified commit to complete.
679  * The caller may not hold the journal lock.
680  */
jbd2_log_wait_commit(journal_t * journal,tid_t tid)681 int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
682 {
683 	int err = 0;
684 
685 	read_lock(&journal->j_state_lock);
686 #ifdef CONFIG_PROVE_LOCKING
687 	/*
688 	 * Some callers make sure transaction is already committing and in that
689 	 * case we cannot block on open handles anymore. So don't warn in that
690 	 * case.
691 	 */
692 	if (tid_gt(tid, journal->j_commit_sequence) &&
693 	    (!journal->j_committing_transaction ||
694 	     journal->j_committing_transaction->t_tid != tid)) {
695 		read_unlock(&journal->j_state_lock);
696 		jbd2_might_wait_for_commit(journal);
697 		read_lock(&journal->j_state_lock);
698 	}
699 #endif
700 #ifdef CONFIG_JBD2_DEBUG
701 	if (!tid_geq(journal->j_commit_request, tid)) {
702 		printk(KERN_ERR
703 		       "%s: error: j_commit_request=%u, tid=%u\n",
704 		       __func__, journal->j_commit_request, tid);
705 	}
706 #endif
707 	while (tid_gt(tid, journal->j_commit_sequence)) {
708 		jbd_debug(1, "JBD2: want %u, j_commit_sequence=%u\n",
709 				  tid, journal->j_commit_sequence);
710 		read_unlock(&journal->j_state_lock);
711 		wake_up(&journal->j_wait_commit);
712 		wait_event(journal->j_wait_done_commit,
713 				!tid_gt(tid, journal->j_commit_sequence));
714 		read_lock(&journal->j_state_lock);
715 	}
716 	read_unlock(&journal->j_state_lock);
717 
718 	if (unlikely(is_journal_aborted(journal)))
719 		err = -EIO;
720 	return err;
721 }
722 
723 /*
724  * Start a fast commit. If there's an ongoing fast or full commit wait for
725  * it to complete. Returns 0 if a new fast commit was started. Returns -EALREADY
726  * if a fast commit is not needed, either because there's an already a commit
727  * going on or this tid has already been committed. Returns -EINVAL if no jbd2
728  * commit has yet been performed.
729  */
jbd2_fc_begin_commit(journal_t * journal,tid_t tid)730 int jbd2_fc_begin_commit(journal_t *journal, tid_t tid)
731 {
732 	if (unlikely(is_journal_aborted(journal)))
733 		return -EIO;
734 	/*
735 	 * Fast commits only allowed if at least one full commit has
736 	 * been processed.
737 	 */
738 	if (!journal->j_stats.ts_tid)
739 		return -EINVAL;
740 
741 	write_lock(&journal->j_state_lock);
742 	if (tid <= journal->j_commit_sequence) {
743 		write_unlock(&journal->j_state_lock);
744 		return -EALREADY;
745 	}
746 
747 	if (journal->j_flags & JBD2_FULL_COMMIT_ONGOING ||
748 	    (journal->j_flags & JBD2_FAST_COMMIT_ONGOING)) {
749 		DEFINE_WAIT(wait);
750 
751 		prepare_to_wait(&journal->j_fc_wait, &wait,
752 				TASK_UNINTERRUPTIBLE);
753 		write_unlock(&journal->j_state_lock);
754 		schedule();
755 		finish_wait(&journal->j_fc_wait, &wait);
756 		return -EALREADY;
757 	}
758 	journal->j_flags |= JBD2_FAST_COMMIT_ONGOING;
759 	write_unlock(&journal->j_state_lock);
760 	jbd2_journal_lock_updates(journal);
761 
762 	return 0;
763 }
764 EXPORT_SYMBOL(jbd2_fc_begin_commit);
765 
766 /*
767  * Stop a fast commit. If fallback is set, this function starts commit of
768  * TID tid before any other fast commit can start.
769  */
__jbd2_fc_end_commit(journal_t * journal,tid_t tid,bool fallback)770 static int __jbd2_fc_end_commit(journal_t *journal, tid_t tid, bool fallback)
771 {
772 	jbd2_journal_unlock_updates(journal);
773 	if (journal->j_fc_cleanup_callback)
774 		journal->j_fc_cleanup_callback(journal, 0, tid);
775 	write_lock(&journal->j_state_lock);
776 	journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
777 	if (fallback)
778 		journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
779 	write_unlock(&journal->j_state_lock);
780 	wake_up(&journal->j_fc_wait);
781 	if (fallback)
782 		return jbd2_complete_transaction(journal, tid);
783 	return 0;
784 }
785 
jbd2_fc_end_commit(journal_t * journal)786 int jbd2_fc_end_commit(journal_t *journal)
787 {
788 	return __jbd2_fc_end_commit(journal, 0, false);
789 }
790 EXPORT_SYMBOL(jbd2_fc_end_commit);
791 
jbd2_fc_end_commit_fallback(journal_t * journal)792 int jbd2_fc_end_commit_fallback(journal_t *journal)
793 {
794 	tid_t tid;
795 
796 	read_lock(&journal->j_state_lock);
797 	tid = journal->j_running_transaction ?
798 		journal->j_running_transaction->t_tid : 0;
799 	read_unlock(&journal->j_state_lock);
800 	return __jbd2_fc_end_commit(journal, tid, true);
801 }
802 EXPORT_SYMBOL(jbd2_fc_end_commit_fallback);
803 
804 /* Return 1 when transaction with given tid has already committed. */
jbd2_transaction_committed(journal_t * journal,tid_t tid)805 int jbd2_transaction_committed(journal_t *journal, tid_t tid)
806 {
807 	int ret = 1;
808 
809 	read_lock(&journal->j_state_lock);
810 	if (journal->j_running_transaction &&
811 	    journal->j_running_transaction->t_tid == tid)
812 		ret = 0;
813 	if (journal->j_committing_transaction &&
814 	    journal->j_committing_transaction->t_tid == tid)
815 		ret = 0;
816 	read_unlock(&journal->j_state_lock);
817 	return ret;
818 }
819 EXPORT_SYMBOL(jbd2_transaction_committed);
820 
821 /*
822  * When this function returns the transaction corresponding to tid
823  * will be completed.  If the transaction has currently running, start
824  * committing that transaction before waiting for it to complete.  If
825  * the transaction id is stale, it is by definition already completed,
826  * so just return SUCCESS.
827  */
jbd2_complete_transaction(journal_t * journal,tid_t tid)828 int jbd2_complete_transaction(journal_t *journal, tid_t tid)
829 {
830 	int	need_to_wait = 1;
831 
832 	read_lock(&journal->j_state_lock);
833 	if (journal->j_running_transaction &&
834 	    journal->j_running_transaction->t_tid == tid) {
835 		if (journal->j_commit_request != tid) {
836 			/* transaction not yet started, so request it */
837 			read_unlock(&journal->j_state_lock);
838 			jbd2_log_start_commit(journal, tid);
839 			goto wait_commit;
840 		}
841 	} else if (!(journal->j_committing_transaction &&
842 		     journal->j_committing_transaction->t_tid == tid))
843 		need_to_wait = 0;
844 	read_unlock(&journal->j_state_lock);
845 	if (!need_to_wait)
846 		return 0;
847 wait_commit:
848 	return jbd2_log_wait_commit(journal, tid);
849 }
850 EXPORT_SYMBOL(jbd2_complete_transaction);
851 
852 /*
853  * Log buffer allocation routines:
854  */
855 
jbd2_journal_next_log_block(journal_t * journal,unsigned long long * retp)856 int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
857 {
858 	unsigned long blocknr;
859 
860 	write_lock(&journal->j_state_lock);
861 	J_ASSERT(journal->j_free > 1);
862 
863 	blocknr = journal->j_head;
864 	journal->j_head++;
865 	journal->j_free--;
866 	if (journal->j_head == journal->j_last)
867 		journal->j_head = journal->j_first;
868 	write_unlock(&journal->j_state_lock);
869 	return jbd2_journal_bmap(journal, blocknr, retp);
870 }
871 
872 /* Map one fast commit buffer for use by the file system */
jbd2_fc_get_buf(journal_t * journal,struct buffer_head ** bh_out)873 int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
874 {
875 	unsigned long long pblock;
876 	unsigned long blocknr;
877 	int ret = 0;
878 	struct buffer_head *bh;
879 	int fc_off;
880 
881 	*bh_out = NULL;
882 
883 	if (journal->j_fc_off + journal->j_fc_first < journal->j_fc_last) {
884 		fc_off = journal->j_fc_off;
885 		blocknr = journal->j_fc_first + fc_off;
886 		journal->j_fc_off++;
887 	} else {
888 		ret = -EINVAL;
889 	}
890 
891 	if (ret)
892 		return ret;
893 
894 	ret = jbd2_journal_bmap(journal, blocknr, &pblock);
895 	if (ret)
896 		return ret;
897 
898 	bh = __getblk(journal->j_dev, pblock, journal->j_blocksize);
899 	if (!bh)
900 		return -ENOMEM;
901 
902 
903 	journal->j_fc_wbuf[fc_off] = bh;
904 
905 	*bh_out = bh;
906 
907 	return 0;
908 }
909 EXPORT_SYMBOL(jbd2_fc_get_buf);
910 
911 /*
912  * Wait on fast commit buffers that were allocated by jbd2_fc_get_buf
913  * for completion.
914  */
jbd2_fc_wait_bufs(journal_t * journal,int num_blks)915 int jbd2_fc_wait_bufs(journal_t *journal, int num_blks)
916 {
917 	struct buffer_head *bh;
918 	int i, j_fc_off;
919 
920 	j_fc_off = journal->j_fc_off;
921 
922 	/*
923 	 * Wait in reverse order to minimize chances of us being woken up before
924 	 * all IOs have completed
925 	 */
926 	for (i = j_fc_off - 1; i >= j_fc_off - num_blks; i--) {
927 		bh = journal->j_fc_wbuf[i];
928 		wait_on_buffer(bh);
929 		put_bh(bh);
930 		journal->j_fc_wbuf[i] = NULL;
931 		if (unlikely(!buffer_uptodate(bh)))
932 			return -EIO;
933 	}
934 
935 	return 0;
936 }
937 EXPORT_SYMBOL(jbd2_fc_wait_bufs);
938 
jbd2_fc_release_bufs(journal_t * journal)939 int jbd2_fc_release_bufs(journal_t *journal)
940 {
941 	struct buffer_head *bh;
942 	int i, j_fc_off;
943 
944 	j_fc_off = journal->j_fc_off;
945 
946 	for (i = j_fc_off - 1; i >= 0; i--) {
947 		bh = journal->j_fc_wbuf[i];
948 		if (!bh)
949 			break;
950 		put_bh(bh);
951 		journal->j_fc_wbuf[i] = NULL;
952 	}
953 
954 	return 0;
955 }
956 EXPORT_SYMBOL(jbd2_fc_release_bufs);
957 
958 /*
959  * Conversion of logical to physical block numbers for the journal
960  *
961  * On external journals the journal blocks are identity-mapped, so
962  * this is a no-op.  If needed, we can use j_blk_offset - everything is
963  * ready.
964  */
jbd2_journal_bmap(journal_t * journal,unsigned long blocknr,unsigned long long * retp)965 int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
966 		 unsigned long long *retp)
967 {
968 	int err = 0;
969 	unsigned long long ret;
970 	sector_t block = 0;
971 
972 	if (journal->j_inode) {
973 		block = blocknr;
974 		ret = bmap(journal->j_inode, &block);
975 
976 		if (ret || !block) {
977 			printk(KERN_ALERT "%s: journal block not found "
978 					"at offset %lu on %s\n",
979 			       __func__, blocknr, journal->j_devname);
980 			err = -EIO;
981 			jbd2_journal_abort(journal, err);
982 		} else {
983 			*retp = block;
984 		}
985 
986 	} else {
987 		*retp = blocknr; /* +journal->j_blk_offset */
988 	}
989 	return err;
990 }
991 
992 /*
993  * We play buffer_head aliasing tricks to write data/metadata blocks to
994  * the journal without copying their contents, but for journal
995  * descriptor blocks we do need to generate bona fide buffers.
996  *
997  * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
998  * the buffer's contents they really should run flush_dcache_page(bh->b_page).
999  * But we don't bother doing that, so there will be coherency problems with
1000  * mmaps of blockdevs which hold live JBD-controlled filesystems.
1001  */
1002 struct buffer_head *
jbd2_journal_get_descriptor_buffer(transaction_t * transaction,int type)1003 jbd2_journal_get_descriptor_buffer(transaction_t *transaction, int type)
1004 {
1005 	journal_t *journal = transaction->t_journal;
1006 	struct buffer_head *bh;
1007 	unsigned long long blocknr;
1008 	journal_header_t *header;
1009 	int err;
1010 
1011 	err = jbd2_journal_next_log_block(journal, &blocknr);
1012 
1013 	if (err)
1014 		return NULL;
1015 
1016 	bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
1017 	if (!bh)
1018 		return NULL;
1019 	atomic_dec(&transaction->t_outstanding_credits);
1020 	lock_buffer(bh);
1021 	memset(bh->b_data, 0, journal->j_blocksize);
1022 	header = (journal_header_t *)bh->b_data;
1023 	header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
1024 	header->h_blocktype = cpu_to_be32(type);
1025 	header->h_sequence = cpu_to_be32(transaction->t_tid);
1026 	set_buffer_uptodate(bh);
1027 	unlock_buffer(bh);
1028 	BUFFER_TRACE(bh, "return this buffer");
1029 	return bh;
1030 }
1031 
jbd2_descriptor_block_csum_set(journal_t * j,struct buffer_head * bh)1032 void jbd2_descriptor_block_csum_set(journal_t *j, struct buffer_head *bh)
1033 {
1034 	struct jbd2_journal_block_tail *tail;
1035 	__u32 csum;
1036 
1037 	if (!jbd2_journal_has_csum_v2or3(j))
1038 		return;
1039 
1040 	tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
1041 			sizeof(struct jbd2_journal_block_tail));
1042 	tail->t_checksum = 0;
1043 	csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
1044 	tail->t_checksum = cpu_to_be32(csum);
1045 }
1046 
1047 /*
1048  * Return tid of the oldest transaction in the journal and block in the journal
1049  * where the transaction starts.
1050  *
1051  * If the journal is now empty, return which will be the next transaction ID
1052  * we will write and where will that transaction start.
1053  *
1054  * The return value is 0 if journal tail cannot be pushed any further, 1 if
1055  * it can.
1056  */
jbd2_journal_get_log_tail(journal_t * journal,tid_t * tid,unsigned long * block)1057 int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
1058 			      unsigned long *block)
1059 {
1060 	transaction_t *transaction;
1061 	int ret;
1062 
1063 	read_lock(&journal->j_state_lock);
1064 	spin_lock(&journal->j_list_lock);
1065 	transaction = journal->j_checkpoint_transactions;
1066 	if (transaction) {
1067 		*tid = transaction->t_tid;
1068 		*block = transaction->t_log_start;
1069 	} else if ((transaction = journal->j_committing_transaction) != NULL) {
1070 		*tid = transaction->t_tid;
1071 		*block = transaction->t_log_start;
1072 	} else if ((transaction = journal->j_running_transaction) != NULL) {
1073 		*tid = transaction->t_tid;
1074 		*block = journal->j_head;
1075 	} else {
1076 		*tid = journal->j_transaction_sequence;
1077 		*block = journal->j_head;
1078 	}
1079 	ret = tid_gt(*tid, journal->j_tail_sequence);
1080 	spin_unlock(&journal->j_list_lock);
1081 	read_unlock(&journal->j_state_lock);
1082 
1083 	return ret;
1084 }
1085 
1086 /*
1087  * Update information in journal structure and in on disk journal superblock
1088  * about log tail. This function does not check whether information passed in
1089  * really pushes log tail further. It's responsibility of the caller to make
1090  * sure provided log tail information is valid (e.g. by holding
1091  * j_checkpoint_mutex all the time between computing log tail and calling this
1092  * function as is the case with jbd2_cleanup_journal_tail()).
1093  *
1094  * Requires j_checkpoint_mutex
1095  */
__jbd2_update_log_tail(journal_t * journal,tid_t tid,unsigned long block)1096 int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
1097 {
1098 	unsigned long freed;
1099 	int ret;
1100 
1101 	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1102 
1103 	/*
1104 	 * We cannot afford for write to remain in drive's caches since as
1105 	 * soon as we update j_tail, next transaction can start reusing journal
1106 	 * space and if we lose sb update during power failure we'd replay
1107 	 * old transaction with possibly newly overwritten data.
1108 	 */
1109 	ret = jbd2_journal_update_sb_log_tail(journal, tid, block,
1110 					      REQ_SYNC | REQ_FUA);
1111 	if (ret)
1112 		goto out;
1113 
1114 	write_lock(&journal->j_state_lock);
1115 	freed = block - journal->j_tail;
1116 	if (block < journal->j_tail)
1117 		freed += journal->j_last - journal->j_first;
1118 
1119 	trace_jbd2_update_log_tail(journal, tid, block, freed);
1120 	jbd_debug(1,
1121 		  "Cleaning journal tail from %u to %u (offset %lu), "
1122 		  "freeing %lu\n",
1123 		  journal->j_tail_sequence, tid, block, freed);
1124 
1125 	journal->j_free += freed;
1126 	journal->j_tail_sequence = tid;
1127 	journal->j_tail = block;
1128 	write_unlock(&journal->j_state_lock);
1129 
1130 out:
1131 	return ret;
1132 }
1133 
1134 /*
1135  * This is a variation of __jbd2_update_log_tail which checks for validity of
1136  * provided log tail and locks j_checkpoint_mutex. So it is safe against races
1137  * with other threads updating log tail.
1138  */
jbd2_update_log_tail(journal_t * journal,tid_t tid,unsigned long block)1139 void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
1140 {
1141 	mutex_lock_io(&journal->j_checkpoint_mutex);
1142 	if (tid_gt(tid, journal->j_tail_sequence))
1143 		__jbd2_update_log_tail(journal, tid, block);
1144 	mutex_unlock(&journal->j_checkpoint_mutex);
1145 }
1146 
1147 struct jbd2_stats_proc_session {
1148 	journal_t *journal;
1149 	struct transaction_stats_s *stats;
1150 	int start;
1151 	int max;
1152 };
1153 
jbd2_seq_info_start(struct seq_file * seq,loff_t * pos)1154 static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
1155 {
1156 	return *pos ? NULL : SEQ_START_TOKEN;
1157 }
1158 
jbd2_seq_info_next(struct seq_file * seq,void * v,loff_t * pos)1159 static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
1160 {
1161 	(*pos)++;
1162 	return NULL;
1163 }
1164 
jbd2_seq_info_show(struct seq_file * seq,void * v)1165 static int jbd2_seq_info_show(struct seq_file *seq, void *v)
1166 {
1167 	struct jbd2_stats_proc_session *s = seq->private;
1168 
1169 	if (v != SEQ_START_TOKEN)
1170 		return 0;
1171 	seq_printf(seq, "%lu transactions (%lu requested), "
1172 		   "each up to %u blocks\n",
1173 		   s->stats->ts_tid, s->stats->ts_requested,
1174 		   s->journal->j_max_transaction_buffers);
1175 	if (s->stats->ts_tid == 0)
1176 		return 0;
1177 	seq_printf(seq, "average: \n  %ums waiting for transaction\n",
1178 	    jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
1179 	seq_printf(seq, "  %ums request delay\n",
1180 	    (s->stats->ts_requested == 0) ? 0 :
1181 	    jiffies_to_msecs(s->stats->run.rs_request_delay /
1182 			     s->stats->ts_requested));
1183 	seq_printf(seq, "  %ums running transaction\n",
1184 	    jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
1185 	seq_printf(seq, "  %ums transaction was being locked\n",
1186 	    jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
1187 	seq_printf(seq, "  %ums flushing data (in ordered mode)\n",
1188 	    jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
1189 	seq_printf(seq, "  %ums logging transaction\n",
1190 	    jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
1191 	seq_printf(seq, "  %lluus average transaction commit time\n",
1192 		   div_u64(s->journal->j_average_commit_time, 1000));
1193 	seq_printf(seq, "  %lu handles per transaction\n",
1194 	    s->stats->run.rs_handle_count / s->stats->ts_tid);
1195 	seq_printf(seq, "  %lu blocks per transaction\n",
1196 	    s->stats->run.rs_blocks / s->stats->ts_tid);
1197 	seq_printf(seq, "  %lu logged blocks per transaction\n",
1198 	    s->stats->run.rs_blocks_logged / s->stats->ts_tid);
1199 	return 0;
1200 }
1201 
jbd2_seq_info_stop(struct seq_file * seq,void * v)1202 static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
1203 {
1204 }
1205 
1206 static const struct seq_operations jbd2_seq_info_ops = {
1207 	.start  = jbd2_seq_info_start,
1208 	.next   = jbd2_seq_info_next,
1209 	.stop   = jbd2_seq_info_stop,
1210 	.show   = jbd2_seq_info_show,
1211 };
1212 
jbd2_seq_info_open(struct inode * inode,struct file * file)1213 static int jbd2_seq_info_open(struct inode *inode, struct file *file)
1214 {
1215 	journal_t *journal = pde_data(inode);
1216 	struct jbd2_stats_proc_session *s;
1217 	int rc, size;
1218 
1219 	s = kmalloc(sizeof(*s), GFP_KERNEL);
1220 	if (s == NULL)
1221 		return -ENOMEM;
1222 	size = sizeof(struct transaction_stats_s);
1223 	s->stats = kmalloc(size, GFP_KERNEL);
1224 	if (s->stats == NULL) {
1225 		kfree(s);
1226 		return -ENOMEM;
1227 	}
1228 	spin_lock(&journal->j_history_lock);
1229 	memcpy(s->stats, &journal->j_stats, size);
1230 	s->journal = journal;
1231 	spin_unlock(&journal->j_history_lock);
1232 
1233 	rc = seq_open(file, &jbd2_seq_info_ops);
1234 	if (rc == 0) {
1235 		struct seq_file *m = file->private_data;
1236 		m->private = s;
1237 	} else {
1238 		kfree(s->stats);
1239 		kfree(s);
1240 	}
1241 	return rc;
1242 
1243 }
1244 
jbd2_seq_info_release(struct inode * inode,struct file * file)1245 static int jbd2_seq_info_release(struct inode *inode, struct file *file)
1246 {
1247 	struct seq_file *seq = file->private_data;
1248 	struct jbd2_stats_proc_session *s = seq->private;
1249 	kfree(s->stats);
1250 	kfree(s);
1251 	return seq_release(inode, file);
1252 }
1253 
1254 static const struct proc_ops jbd2_info_proc_ops = {
1255 	.proc_open	= jbd2_seq_info_open,
1256 	.proc_read	= seq_read,
1257 	.proc_lseek	= seq_lseek,
1258 	.proc_release	= jbd2_seq_info_release,
1259 };
1260 
1261 static struct proc_dir_entry *proc_jbd2_stats;
1262 
jbd2_stats_proc_init(journal_t * journal)1263 static void jbd2_stats_proc_init(journal_t *journal)
1264 {
1265 	journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
1266 	if (journal->j_proc_entry) {
1267 		proc_create_data("info", S_IRUGO, journal->j_proc_entry,
1268 				 &jbd2_info_proc_ops, journal);
1269 	}
1270 }
1271 
jbd2_stats_proc_exit(journal_t * journal)1272 static void jbd2_stats_proc_exit(journal_t *journal)
1273 {
1274 	remove_proc_entry("info", journal->j_proc_entry);
1275 	remove_proc_entry(journal->j_devname, proc_jbd2_stats);
1276 }
1277 
1278 /* Minimum size of descriptor tag */
jbd2_min_tag_size(void)1279 static int jbd2_min_tag_size(void)
1280 {
1281 	/*
1282 	 * Tag with 32-bit block numbers does not use last four bytes of the
1283 	 * structure
1284 	 */
1285 	return sizeof(journal_block_tag_t) - 4;
1286 }
1287 
1288 /**
1289  * jbd2_journal_shrink_scan()
1290  * @shrink: shrinker to work on
1291  * @sc: reclaim request to process
1292  *
1293  * Scan the checkpointed buffer on the checkpoint list and release the
1294  * journal_head.
1295  */
jbd2_journal_shrink_scan(struct shrinker * shrink,struct shrink_control * sc)1296 static unsigned long jbd2_journal_shrink_scan(struct shrinker *shrink,
1297 					      struct shrink_control *sc)
1298 {
1299 	journal_t *journal = container_of(shrink, journal_t, j_shrinker);
1300 	unsigned long nr_to_scan = sc->nr_to_scan;
1301 	unsigned long nr_shrunk;
1302 	unsigned long count;
1303 
1304 	count = percpu_counter_read_positive(&journal->j_checkpoint_jh_count);
1305 	trace_jbd2_shrink_scan_enter(journal, sc->nr_to_scan, count);
1306 
1307 	nr_shrunk = jbd2_journal_shrink_checkpoint_list(journal, &nr_to_scan);
1308 
1309 	count = percpu_counter_read_positive(&journal->j_checkpoint_jh_count);
1310 	trace_jbd2_shrink_scan_exit(journal, nr_to_scan, nr_shrunk, count);
1311 
1312 	return nr_shrunk;
1313 }
1314 
1315 /**
1316  * jbd2_journal_shrink_count()
1317  * @shrink: shrinker to work on
1318  * @sc: reclaim request to process
1319  *
1320  * Count the number of checkpoint buffers on the checkpoint list.
1321  */
jbd2_journal_shrink_count(struct shrinker * shrink,struct shrink_control * sc)1322 static unsigned long jbd2_journal_shrink_count(struct shrinker *shrink,
1323 					       struct shrink_control *sc)
1324 {
1325 	journal_t *journal = container_of(shrink, journal_t, j_shrinker);
1326 	unsigned long count;
1327 
1328 	count = percpu_counter_read_positive(&journal->j_checkpoint_jh_count);
1329 	trace_jbd2_shrink_count(journal, sc->nr_to_scan, count);
1330 
1331 	return count;
1332 }
1333 
1334 /*
1335  * Management for journal control blocks: functions to create and
1336  * destroy journal_t structures, and to initialise and read existing
1337  * journal blocks from disk.  */
1338 
1339 /* First: create and setup a journal_t object in memory.  We initialise
1340  * very few fields yet: that has to wait until we have created the
1341  * journal structures from from scratch, or loaded them from disk. */
1342 
journal_init_common(struct block_device * bdev,struct block_device * fs_dev,unsigned long long start,int len,int blocksize)1343 static journal_t *journal_init_common(struct block_device *bdev,
1344 			struct block_device *fs_dev,
1345 			unsigned long long start, int len, int blocksize)
1346 {
1347 	static struct lock_class_key jbd2_trans_commit_key;
1348 	journal_t *journal;
1349 	int err;
1350 	struct buffer_head *bh;
1351 	int n;
1352 
1353 	journal = kzalloc(sizeof(*journal), GFP_KERNEL);
1354 	if (!journal)
1355 		return NULL;
1356 
1357 	init_waitqueue_head(&journal->j_wait_transaction_locked);
1358 	init_waitqueue_head(&journal->j_wait_done_commit);
1359 	init_waitqueue_head(&journal->j_wait_commit);
1360 	init_waitqueue_head(&journal->j_wait_updates);
1361 	init_waitqueue_head(&journal->j_wait_reserved);
1362 	init_waitqueue_head(&journal->j_fc_wait);
1363 	mutex_init(&journal->j_abort_mutex);
1364 	mutex_init(&journal->j_barrier);
1365 	mutex_init(&journal->j_checkpoint_mutex);
1366 	spin_lock_init(&journal->j_revoke_lock);
1367 	spin_lock_init(&journal->j_list_lock);
1368 	rwlock_init(&journal->j_state_lock);
1369 
1370 	journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
1371 	journal->j_min_batch_time = 0;
1372 	journal->j_max_batch_time = 15000; /* 15ms */
1373 	atomic_set(&journal->j_reserved_credits, 0);
1374 
1375 	/* The journal is marked for error until we succeed with recovery! */
1376 	journal->j_flags = JBD2_ABORT;
1377 
1378 	/* Set up a default-sized revoke table for the new mount. */
1379 	err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
1380 	if (err)
1381 		goto err_cleanup;
1382 
1383 	spin_lock_init(&journal->j_history_lock);
1384 
1385 	lockdep_init_map(&journal->j_trans_commit_map, "jbd2_handle",
1386 			 &jbd2_trans_commit_key, 0);
1387 
1388 	/* journal descriptor can store up to n blocks -bzzz */
1389 	journal->j_blocksize = blocksize;
1390 	journal->j_dev = bdev;
1391 	journal->j_fs_dev = fs_dev;
1392 	journal->j_blk_offset = start;
1393 	journal->j_total_len = len;
1394 	/* We need enough buffers to write out full descriptor block. */
1395 	n = journal->j_blocksize / jbd2_min_tag_size();
1396 	journal->j_wbufsize = n;
1397 	journal->j_fc_wbuf = NULL;
1398 	journal->j_wbuf = kmalloc_array(n, sizeof(struct buffer_head *),
1399 					GFP_KERNEL);
1400 	if (!journal->j_wbuf)
1401 		goto err_cleanup;
1402 
1403 	bh = getblk_unmovable(journal->j_dev, start, journal->j_blocksize);
1404 	if (!bh) {
1405 		pr_err("%s: Cannot get buffer for journal superblock\n",
1406 			__func__);
1407 		goto err_cleanup;
1408 	}
1409 	journal->j_sb_buffer = bh;
1410 	journal->j_superblock = (journal_superblock_t *)bh->b_data;
1411 
1412 	journal->j_shrink_transaction = NULL;
1413 	journal->j_shrinker.scan_objects = jbd2_journal_shrink_scan;
1414 	journal->j_shrinker.count_objects = jbd2_journal_shrink_count;
1415 	journal->j_shrinker.seeks = DEFAULT_SEEKS;
1416 	journal->j_shrinker.batch = journal->j_max_transaction_buffers;
1417 
1418 	if (percpu_counter_init(&journal->j_checkpoint_jh_count, 0, GFP_KERNEL))
1419 		goto err_cleanup;
1420 
1421 	if (register_shrinker(&journal->j_shrinker)) {
1422 		percpu_counter_destroy(&journal->j_checkpoint_jh_count);
1423 		goto err_cleanup;
1424 	}
1425 	return journal;
1426 
1427 err_cleanup:
1428 	brelse(journal->j_sb_buffer);
1429 	kfree(journal->j_wbuf);
1430 	jbd2_journal_destroy_revoke(journal);
1431 	kfree(journal);
1432 	return NULL;
1433 }
1434 
1435 /* jbd2_journal_init_dev and jbd2_journal_init_inode:
1436  *
1437  * Create a journal structure assigned some fixed set of disk blocks to
1438  * the journal.  We don't actually touch those disk blocks yet, but we
1439  * need to set up all of the mapping information to tell the journaling
1440  * system where the journal blocks are.
1441  *
1442  */
1443 
1444 /**
1445  *  journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
1446  *  @bdev: Block device on which to create the journal
1447  *  @fs_dev: Device which hold journalled filesystem for this journal.
1448  *  @start: Block nr Start of journal.
1449  *  @len:  Length of the journal in blocks.
1450  *  @blocksize: blocksize of journalling device
1451  *
1452  *  Returns: a newly created journal_t *
1453  *
1454  *  jbd2_journal_init_dev creates a journal which maps a fixed contiguous
1455  *  range of blocks on an arbitrary block device.
1456  *
1457  */
jbd2_journal_init_dev(struct block_device * bdev,struct block_device * fs_dev,unsigned long long start,int len,int blocksize)1458 journal_t *jbd2_journal_init_dev(struct block_device *bdev,
1459 			struct block_device *fs_dev,
1460 			unsigned long long start, int len, int blocksize)
1461 {
1462 	journal_t *journal;
1463 
1464 	journal = journal_init_common(bdev, fs_dev, start, len, blocksize);
1465 	if (!journal)
1466 		return NULL;
1467 
1468 	bdevname(journal->j_dev, journal->j_devname);
1469 	strreplace(journal->j_devname, '/', '!');
1470 	jbd2_stats_proc_init(journal);
1471 
1472 	return journal;
1473 }
1474 
1475 /**
1476  *  journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
1477  *  @inode: An inode to create the journal in
1478  *
1479  * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
1480  * the journal.  The inode must exist already, must support bmap() and
1481  * must have all data blocks preallocated.
1482  */
jbd2_journal_init_inode(struct inode * inode)1483 journal_t *jbd2_journal_init_inode(struct inode *inode)
1484 {
1485 	journal_t *journal;
1486 	sector_t blocknr;
1487 	char *p;
1488 	int err = 0;
1489 
1490 	blocknr = 0;
1491 	err = bmap(inode, &blocknr);
1492 
1493 	if (err || !blocknr) {
1494 		pr_err("%s: Cannot locate journal superblock\n",
1495 			__func__);
1496 		return NULL;
1497 	}
1498 
1499 	jbd_debug(1, "JBD2: inode %s/%ld, size %lld, bits %d, blksize %ld\n",
1500 		  inode->i_sb->s_id, inode->i_ino, (long long) inode->i_size,
1501 		  inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
1502 
1503 	journal = journal_init_common(inode->i_sb->s_bdev, inode->i_sb->s_bdev,
1504 			blocknr, inode->i_size >> inode->i_sb->s_blocksize_bits,
1505 			inode->i_sb->s_blocksize);
1506 	if (!journal)
1507 		return NULL;
1508 
1509 	journal->j_inode = inode;
1510 	bdevname(journal->j_dev, journal->j_devname);
1511 	p = strreplace(journal->j_devname, '/', '!');
1512 	sprintf(p, "-%lu", journal->j_inode->i_ino);
1513 	jbd2_stats_proc_init(journal);
1514 
1515 	return journal;
1516 }
1517 
1518 /*
1519  * If the journal init or create aborts, we need to mark the journal
1520  * superblock as being NULL to prevent the journal destroy from writing
1521  * back a bogus superblock.
1522  */
journal_fail_superblock(journal_t * journal)1523 static void journal_fail_superblock(journal_t *journal)
1524 {
1525 	struct buffer_head *bh = journal->j_sb_buffer;
1526 	brelse(bh);
1527 	journal->j_sb_buffer = NULL;
1528 }
1529 
1530 /*
1531  * Given a journal_t structure, initialise the various fields for
1532  * startup of a new journaling session.  We use this both when creating
1533  * a journal, and after recovering an old journal to reset it for
1534  * subsequent use.
1535  */
1536 
journal_reset(journal_t * journal)1537 static int journal_reset(journal_t *journal)
1538 {
1539 	journal_superblock_t *sb = journal->j_superblock;
1540 	unsigned long long first, last;
1541 
1542 	first = be32_to_cpu(sb->s_first);
1543 	last = be32_to_cpu(sb->s_maxlen);
1544 	if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
1545 		printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n",
1546 		       first, last);
1547 		journal_fail_superblock(journal);
1548 		return -EINVAL;
1549 	}
1550 
1551 	journal->j_first = first;
1552 	journal->j_last = last;
1553 
1554 	journal->j_head = journal->j_first;
1555 	journal->j_tail = journal->j_first;
1556 	journal->j_free = journal->j_last - journal->j_first;
1557 
1558 	journal->j_tail_sequence = journal->j_transaction_sequence;
1559 	journal->j_commit_sequence = journal->j_transaction_sequence - 1;
1560 	journal->j_commit_request = journal->j_commit_sequence;
1561 
1562 	journal->j_max_transaction_buffers = jbd2_journal_get_max_txn_bufs(journal);
1563 
1564 	/*
1565 	 * Now that journal recovery is done, turn fast commits off here. This
1566 	 * way, if fast commit was enabled before the crash but if now FS has
1567 	 * disabled it, we don't enable fast commits.
1568 	 */
1569 	jbd2_clear_feature_fast_commit(journal);
1570 
1571 	/*
1572 	 * As a special case, if the on-disk copy is already marked as needing
1573 	 * no recovery (s_start == 0), then we can safely defer the superblock
1574 	 * update until the next commit by setting JBD2_FLUSHED.  This avoids
1575 	 * attempting a write to a potential-readonly device.
1576 	 */
1577 	if (sb->s_start == 0) {
1578 		jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
1579 			"(start %ld, seq %u, errno %d)\n",
1580 			journal->j_tail, journal->j_tail_sequence,
1581 			journal->j_errno);
1582 		journal->j_flags |= JBD2_FLUSHED;
1583 	} else {
1584 		/* Lock here to make assertions happy... */
1585 		mutex_lock_io(&journal->j_checkpoint_mutex);
1586 		/*
1587 		 * Update log tail information. We use REQ_FUA since new
1588 		 * transaction will start reusing journal space and so we
1589 		 * must make sure information about current log tail is on
1590 		 * disk before that.
1591 		 */
1592 		jbd2_journal_update_sb_log_tail(journal,
1593 						journal->j_tail_sequence,
1594 						journal->j_tail,
1595 						REQ_SYNC | REQ_FUA);
1596 		mutex_unlock(&journal->j_checkpoint_mutex);
1597 	}
1598 	return jbd2_journal_start_thread(journal);
1599 }
1600 
1601 /*
1602  * This function expects that the caller will have locked the journal
1603  * buffer head, and will return with it unlocked
1604  */
jbd2_write_superblock(journal_t * journal,int write_flags)1605 static int jbd2_write_superblock(journal_t *journal, int write_flags)
1606 {
1607 	struct buffer_head *bh = journal->j_sb_buffer;
1608 	journal_superblock_t *sb = journal->j_superblock;
1609 	int ret;
1610 
1611 	/* Buffer got discarded which means block device got invalidated */
1612 	if (!buffer_mapped(bh)) {
1613 		unlock_buffer(bh);
1614 		return -EIO;
1615 	}
1616 
1617 	trace_jbd2_write_superblock(journal, write_flags);
1618 	if (!(journal->j_flags & JBD2_BARRIER))
1619 		write_flags &= ~(REQ_FUA | REQ_PREFLUSH);
1620 	if (buffer_write_io_error(bh)) {
1621 		/*
1622 		 * Oh, dear.  A previous attempt to write the journal
1623 		 * superblock failed.  This could happen because the
1624 		 * USB device was yanked out.  Or it could happen to
1625 		 * be a transient write error and maybe the block will
1626 		 * be remapped.  Nothing we can do but to retry the
1627 		 * write and hope for the best.
1628 		 */
1629 		printk(KERN_ERR "JBD2: previous I/O error detected "
1630 		       "for journal superblock update for %s.\n",
1631 		       journal->j_devname);
1632 		clear_buffer_write_io_error(bh);
1633 		set_buffer_uptodate(bh);
1634 	}
1635 	if (jbd2_journal_has_csum_v2or3(journal))
1636 		sb->s_checksum = jbd2_superblock_csum(journal, sb);
1637 	get_bh(bh);
1638 	bh->b_end_io = end_buffer_write_sync;
1639 	ret = submit_bh(REQ_OP_WRITE, write_flags, bh);
1640 	wait_on_buffer(bh);
1641 	if (buffer_write_io_error(bh)) {
1642 		clear_buffer_write_io_error(bh);
1643 		set_buffer_uptodate(bh);
1644 		ret = -EIO;
1645 	}
1646 	if (ret) {
1647 		printk(KERN_ERR "JBD2: Error %d detected when updating "
1648 		       "journal superblock for %s.\n", ret,
1649 		       journal->j_devname);
1650 		if (!is_journal_aborted(journal))
1651 			jbd2_journal_abort(journal, ret);
1652 	}
1653 
1654 	return ret;
1655 }
1656 
1657 /**
1658  * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
1659  * @journal: The journal to update.
1660  * @tail_tid: TID of the new transaction at the tail of the log
1661  * @tail_block: The first block of the transaction at the tail of the log
1662  * @write_op: With which operation should we write the journal sb
1663  *
1664  * Update a journal's superblock information about log tail and write it to
1665  * disk, waiting for the IO to complete.
1666  */
jbd2_journal_update_sb_log_tail(journal_t * journal,tid_t tail_tid,unsigned long tail_block,int write_op)1667 int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
1668 				     unsigned long tail_block, int write_op)
1669 {
1670 	journal_superblock_t *sb = journal->j_superblock;
1671 	int ret;
1672 
1673 	if (is_journal_aborted(journal))
1674 		return -EIO;
1675 	if (test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags)) {
1676 		jbd2_journal_abort(journal, -EIO);
1677 		return -EIO;
1678 	}
1679 
1680 	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1681 	jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
1682 		  tail_block, tail_tid);
1683 
1684 	lock_buffer(journal->j_sb_buffer);
1685 	sb->s_sequence = cpu_to_be32(tail_tid);
1686 	sb->s_start    = cpu_to_be32(tail_block);
1687 
1688 	ret = jbd2_write_superblock(journal, write_op);
1689 	if (ret)
1690 		goto out;
1691 
1692 	/* Log is no longer empty */
1693 	write_lock(&journal->j_state_lock);
1694 	WARN_ON(!sb->s_sequence);
1695 	journal->j_flags &= ~JBD2_FLUSHED;
1696 	write_unlock(&journal->j_state_lock);
1697 
1698 out:
1699 	return ret;
1700 }
1701 
1702 /**
1703  * jbd2_mark_journal_empty() - Mark on disk journal as empty.
1704  * @journal: The journal to update.
1705  * @write_op: With which operation should we write the journal sb
1706  *
1707  * Update a journal's dynamic superblock fields to show that journal is empty.
1708  * Write updated superblock to disk waiting for IO to complete.
1709  */
jbd2_mark_journal_empty(journal_t * journal,int write_op)1710 static void jbd2_mark_journal_empty(journal_t *journal, int write_op)
1711 {
1712 	journal_superblock_t *sb = journal->j_superblock;
1713 	bool had_fast_commit = false;
1714 
1715 	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1716 	lock_buffer(journal->j_sb_buffer);
1717 	if (sb->s_start == 0) {		/* Is it already empty? */
1718 		unlock_buffer(journal->j_sb_buffer);
1719 		return;
1720 	}
1721 
1722 	jbd_debug(1, "JBD2: Marking journal as empty (seq %u)\n",
1723 		  journal->j_tail_sequence);
1724 
1725 	sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
1726 	sb->s_start    = cpu_to_be32(0);
1727 	if (jbd2_has_feature_fast_commit(journal)) {
1728 		/*
1729 		 * When journal is clean, no need to commit fast commit flag and
1730 		 * make file system incompatible with older kernels.
1731 		 */
1732 		jbd2_clear_feature_fast_commit(journal);
1733 		had_fast_commit = true;
1734 	}
1735 
1736 	jbd2_write_superblock(journal, write_op);
1737 
1738 	if (had_fast_commit)
1739 		jbd2_set_feature_fast_commit(journal);
1740 
1741 	/* Log is no longer empty */
1742 	write_lock(&journal->j_state_lock);
1743 	journal->j_flags |= JBD2_FLUSHED;
1744 	write_unlock(&journal->j_state_lock);
1745 }
1746 
1747 /**
1748  * __jbd2_journal_erase() - Discard or zeroout journal blocks (excluding superblock)
1749  * @journal: The journal to erase.
1750  * @flags: A discard/zeroout request is sent for each physically contigous
1751  *	region of the journal. Either JBD2_JOURNAL_FLUSH_DISCARD or
1752  *	JBD2_JOURNAL_FLUSH_ZEROOUT must be set to determine which operation
1753  *	to perform.
1754  *
1755  * Note: JBD2_JOURNAL_FLUSH_ZEROOUT attempts to use hardware offload. Zeroes
1756  * will be explicitly written if no hardware offload is available, see
1757  * blkdev_issue_zeroout for more details.
1758  */
__jbd2_journal_erase(journal_t * journal,unsigned int flags)1759 static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
1760 {
1761 	int err = 0;
1762 	unsigned long block, log_offset; /* logical */
1763 	unsigned long long phys_block, block_start, block_stop; /* physical */
1764 	loff_t byte_start, byte_stop, byte_count;
1765 
1766 	/* flags must be set to either discard or zeroout */
1767 	if ((flags & ~JBD2_JOURNAL_FLUSH_VALID) || !flags ||
1768 			((flags & JBD2_JOURNAL_FLUSH_DISCARD) &&
1769 			(flags & JBD2_JOURNAL_FLUSH_ZEROOUT)))
1770 		return -EINVAL;
1771 
1772 	if ((flags & JBD2_JOURNAL_FLUSH_DISCARD) &&
1773 	    !bdev_max_discard_sectors(journal->j_dev))
1774 		return -EOPNOTSUPP;
1775 
1776 	/*
1777 	 * lookup block mapping and issue discard/zeroout for each
1778 	 * contiguous region
1779 	 */
1780 	log_offset = be32_to_cpu(journal->j_superblock->s_first);
1781 	block_start =  ~0ULL;
1782 	for (block = log_offset; block < journal->j_total_len; block++) {
1783 		err = jbd2_journal_bmap(journal, block, &phys_block);
1784 		if (err) {
1785 			pr_err("JBD2: bad block at offset %lu", block);
1786 			return err;
1787 		}
1788 
1789 		if (block_start == ~0ULL) {
1790 			block_start = phys_block;
1791 			block_stop = block_start - 1;
1792 		}
1793 
1794 		/*
1795 		 * last block not contiguous with current block,
1796 		 * process last contiguous region and return to this block on
1797 		 * next loop
1798 		 */
1799 		if (phys_block != block_stop + 1) {
1800 			block--;
1801 		} else {
1802 			block_stop++;
1803 			/*
1804 			 * if this isn't the last block of journal,
1805 			 * no need to process now because next block may also
1806 			 * be part of this contiguous region
1807 			 */
1808 			if (block != journal->j_total_len - 1)
1809 				continue;
1810 		}
1811 
1812 		/*
1813 		 * end of contiguous region or this is last block of journal,
1814 		 * take care of the region
1815 		 */
1816 		byte_start = block_start * journal->j_blocksize;
1817 		byte_stop = block_stop * journal->j_blocksize;
1818 		byte_count = (block_stop - block_start + 1) *
1819 				journal->j_blocksize;
1820 
1821 		truncate_inode_pages_range(journal->j_dev->bd_inode->i_mapping,
1822 				byte_start, byte_stop);
1823 
1824 		if (flags & JBD2_JOURNAL_FLUSH_DISCARD) {
1825 			err = blkdev_issue_discard(journal->j_dev,
1826 					byte_start >> SECTOR_SHIFT,
1827 					byte_count >> SECTOR_SHIFT,
1828 					GFP_NOFS);
1829 		} else if (flags & JBD2_JOURNAL_FLUSH_ZEROOUT) {
1830 			err = blkdev_issue_zeroout(journal->j_dev,
1831 					byte_start >> SECTOR_SHIFT,
1832 					byte_count >> SECTOR_SHIFT,
1833 					GFP_NOFS, 0);
1834 		}
1835 
1836 		if (unlikely(err != 0)) {
1837 			pr_err("JBD2: (error %d) unable to wipe journal at physical blocks %llu - %llu",
1838 					err, block_start, block_stop);
1839 			return err;
1840 		}
1841 
1842 		/* reset start and stop after processing a region */
1843 		block_start = ~0ULL;
1844 	}
1845 
1846 	return blkdev_issue_flush(journal->j_dev);
1847 }
1848 
1849 /**
1850  * jbd2_journal_update_sb_errno() - Update error in the journal.
1851  * @journal: The journal to update.
1852  *
1853  * Update a journal's errno.  Write updated superblock to disk waiting for IO
1854  * to complete.
1855  */
jbd2_journal_update_sb_errno(journal_t * journal)1856 void jbd2_journal_update_sb_errno(journal_t *journal)
1857 {
1858 	journal_superblock_t *sb = journal->j_superblock;
1859 	int errcode;
1860 
1861 	lock_buffer(journal->j_sb_buffer);
1862 	errcode = journal->j_errno;
1863 	if (errcode == -ESHUTDOWN)
1864 		errcode = 0;
1865 	jbd_debug(1, "JBD2: updating superblock error (errno %d)\n", errcode);
1866 	sb->s_errno    = cpu_to_be32(errcode);
1867 
1868 	jbd2_write_superblock(journal, REQ_SYNC | REQ_FUA);
1869 }
1870 EXPORT_SYMBOL(jbd2_journal_update_sb_errno);
1871 
journal_revoke_records_per_block(journal_t * journal)1872 static int journal_revoke_records_per_block(journal_t *journal)
1873 {
1874 	int record_size;
1875 	int space = journal->j_blocksize - sizeof(jbd2_journal_revoke_header_t);
1876 
1877 	if (jbd2_has_feature_64bit(journal))
1878 		record_size = 8;
1879 	else
1880 		record_size = 4;
1881 
1882 	if (jbd2_journal_has_csum_v2or3(journal))
1883 		space -= sizeof(struct jbd2_journal_block_tail);
1884 	return space / record_size;
1885 }
1886 
1887 /*
1888  * Read the superblock for a given journal, performing initial
1889  * validation of the format.
1890  */
journal_get_superblock(journal_t * journal)1891 static int journal_get_superblock(journal_t *journal)
1892 {
1893 	struct buffer_head *bh;
1894 	journal_superblock_t *sb;
1895 	int err = -EIO;
1896 
1897 	bh = journal->j_sb_buffer;
1898 
1899 	J_ASSERT(bh != NULL);
1900 	if (!buffer_uptodate(bh)) {
1901 		ll_rw_block(REQ_OP_READ, 0, 1, &bh);
1902 		wait_on_buffer(bh);
1903 		if (!buffer_uptodate(bh)) {
1904 			printk(KERN_ERR
1905 				"JBD2: IO error reading journal superblock\n");
1906 			goto out;
1907 		}
1908 	}
1909 
1910 	if (buffer_verified(bh))
1911 		return 0;
1912 
1913 	sb = journal->j_superblock;
1914 
1915 	err = -EINVAL;
1916 
1917 	if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1918 	    sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1919 		printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
1920 		goto out;
1921 	}
1922 
1923 	switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1924 	case JBD2_SUPERBLOCK_V1:
1925 		journal->j_format_version = 1;
1926 		break;
1927 	case JBD2_SUPERBLOCK_V2:
1928 		journal->j_format_version = 2;
1929 		break;
1930 	default:
1931 		printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
1932 		goto out;
1933 	}
1934 
1935 	if (be32_to_cpu(sb->s_maxlen) < journal->j_total_len)
1936 		journal->j_total_len = be32_to_cpu(sb->s_maxlen);
1937 	else if (be32_to_cpu(sb->s_maxlen) > journal->j_total_len) {
1938 		printk(KERN_WARNING "JBD2: journal file too short\n");
1939 		goto out;
1940 	}
1941 
1942 	if (be32_to_cpu(sb->s_first) == 0 ||
1943 	    be32_to_cpu(sb->s_first) >= journal->j_total_len) {
1944 		printk(KERN_WARNING
1945 			"JBD2: Invalid start block of journal: %u\n",
1946 			be32_to_cpu(sb->s_first));
1947 		goto out;
1948 	}
1949 
1950 	if (jbd2_has_feature_csum2(journal) &&
1951 	    jbd2_has_feature_csum3(journal)) {
1952 		/* Can't have checksum v2 and v3 at the same time! */
1953 		printk(KERN_ERR "JBD2: Can't enable checksumming v2 and v3 "
1954 		       "at the same time!\n");
1955 		goto out;
1956 	}
1957 
1958 	if (jbd2_journal_has_csum_v2or3_feature(journal) &&
1959 	    jbd2_has_feature_checksum(journal)) {
1960 		/* Can't have checksum v1 and v2 on at the same time! */
1961 		printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
1962 		       "at the same time!\n");
1963 		goto out;
1964 	}
1965 
1966 	if (!jbd2_verify_csum_type(journal, sb)) {
1967 		printk(KERN_ERR "JBD2: Unknown checksum type\n");
1968 		goto out;
1969 	}
1970 
1971 	/* Load the checksum driver */
1972 	if (jbd2_journal_has_csum_v2or3_feature(journal)) {
1973 		journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
1974 		if (IS_ERR(journal->j_chksum_driver)) {
1975 			printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
1976 			err = PTR_ERR(journal->j_chksum_driver);
1977 			journal->j_chksum_driver = NULL;
1978 			goto out;
1979 		}
1980 	}
1981 
1982 	if (jbd2_journal_has_csum_v2or3(journal)) {
1983 		/* Check superblock checksum */
1984 		if (sb->s_checksum != jbd2_superblock_csum(journal, sb)) {
1985 			printk(KERN_ERR "JBD2: journal checksum error\n");
1986 			err = -EFSBADCRC;
1987 			goto out;
1988 		}
1989 
1990 		/* Precompute checksum seed for all metadata */
1991 		journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
1992 						   sizeof(sb->s_uuid));
1993 	}
1994 
1995 	journal->j_revoke_records_per_block =
1996 				journal_revoke_records_per_block(journal);
1997 	set_buffer_verified(bh);
1998 
1999 	return 0;
2000 
2001 out:
2002 	journal_fail_superblock(journal);
2003 	return err;
2004 }
2005 
2006 /*
2007  * Load the on-disk journal superblock and read the key fields into the
2008  * journal_t.
2009  */
2010 
load_superblock(journal_t * journal)2011 static int load_superblock(journal_t *journal)
2012 {
2013 	int err;
2014 	journal_superblock_t *sb;
2015 	int num_fc_blocks;
2016 
2017 	err = journal_get_superblock(journal);
2018 	if (err)
2019 		return err;
2020 
2021 	sb = journal->j_superblock;
2022 
2023 	journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
2024 	journal->j_tail = be32_to_cpu(sb->s_start);
2025 	journal->j_first = be32_to_cpu(sb->s_first);
2026 	journal->j_errno = be32_to_cpu(sb->s_errno);
2027 	journal->j_last = be32_to_cpu(sb->s_maxlen);
2028 
2029 	if (jbd2_has_feature_fast_commit(journal)) {
2030 		journal->j_fc_last = be32_to_cpu(sb->s_maxlen);
2031 		num_fc_blocks = jbd2_journal_get_num_fc_blks(sb);
2032 		if (journal->j_last - num_fc_blocks >= JBD2_MIN_JOURNAL_BLOCKS)
2033 			journal->j_last = journal->j_fc_last - num_fc_blocks;
2034 		journal->j_fc_first = journal->j_last + 1;
2035 		journal->j_fc_off = 0;
2036 	}
2037 
2038 	return 0;
2039 }
2040 
2041 
2042 /**
2043  * jbd2_journal_load() - Read journal from disk.
2044  * @journal: Journal to act on.
2045  *
2046  * Given a journal_t structure which tells us which disk blocks contain
2047  * a journal, read the journal from disk to initialise the in-memory
2048  * structures.
2049  */
jbd2_journal_load(journal_t * journal)2050 int jbd2_journal_load(journal_t *journal)
2051 {
2052 	int err;
2053 	journal_superblock_t *sb;
2054 
2055 	err = load_superblock(journal);
2056 	if (err)
2057 		return err;
2058 
2059 	sb = journal->j_superblock;
2060 	/* If this is a V2 superblock, then we have to check the
2061 	 * features flags on it. */
2062 
2063 	if (journal->j_format_version >= 2) {
2064 		if ((sb->s_feature_ro_compat &
2065 		     ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
2066 		    (sb->s_feature_incompat &
2067 		     ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
2068 			printk(KERN_WARNING
2069 				"JBD2: Unrecognised features on journal\n");
2070 			return -EINVAL;
2071 		}
2072 	}
2073 
2074 	/*
2075 	 * Create a slab for this blocksize
2076 	 */
2077 	err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
2078 	if (err)
2079 		return err;
2080 
2081 	/* Let the recovery code check whether it needs to recover any
2082 	 * data from the journal. */
2083 	if (jbd2_journal_recover(journal))
2084 		goto recovery_error;
2085 
2086 	if (journal->j_failed_commit) {
2087 		printk(KERN_ERR "JBD2: journal transaction %u on %s "
2088 		       "is corrupt.\n", journal->j_failed_commit,
2089 		       journal->j_devname);
2090 		return -EFSCORRUPTED;
2091 	}
2092 	/*
2093 	 * clear JBD2_ABORT flag initialized in journal_init_common
2094 	 * here to update log tail information with the newest seq.
2095 	 */
2096 	journal->j_flags &= ~JBD2_ABORT;
2097 
2098 	/* OK, we've finished with the dynamic journal bits:
2099 	 * reinitialise the dynamic contents of the superblock in memory
2100 	 * and reset them on disk. */
2101 	if (journal_reset(journal))
2102 		goto recovery_error;
2103 
2104 	journal->j_flags |= JBD2_LOADED;
2105 	return 0;
2106 
2107 recovery_error:
2108 	printk(KERN_WARNING "JBD2: recovery failed\n");
2109 	return -EIO;
2110 }
2111 
2112 /**
2113  * jbd2_journal_destroy() - Release a journal_t structure.
2114  * @journal: Journal to act on.
2115  *
2116  * Release a journal_t structure once it is no longer in use by the
2117  * journaled object.
2118  * Return <0 if we couldn't clean up the journal.
2119  */
jbd2_journal_destroy(journal_t * journal)2120 int jbd2_journal_destroy(journal_t *journal)
2121 {
2122 	int err = 0;
2123 
2124 	/* Wait for the commit thread to wake up and die. */
2125 	journal_kill_thread(journal);
2126 
2127 	/* Force a final log commit */
2128 	if (journal->j_running_transaction)
2129 		jbd2_journal_commit_transaction(journal);
2130 
2131 	/* Force any old transactions to disk */
2132 
2133 	/* Totally anal locking here... */
2134 	spin_lock(&journal->j_list_lock);
2135 	while (journal->j_checkpoint_transactions != NULL) {
2136 		spin_unlock(&journal->j_list_lock);
2137 		mutex_lock_io(&journal->j_checkpoint_mutex);
2138 		err = jbd2_log_do_checkpoint(journal);
2139 		mutex_unlock(&journal->j_checkpoint_mutex);
2140 		/*
2141 		 * If checkpointing failed, just free the buffers to avoid
2142 		 * looping forever
2143 		 */
2144 		if (err) {
2145 			jbd2_journal_destroy_checkpoint(journal);
2146 			spin_lock(&journal->j_list_lock);
2147 			break;
2148 		}
2149 		spin_lock(&journal->j_list_lock);
2150 	}
2151 
2152 	J_ASSERT(journal->j_running_transaction == NULL);
2153 	J_ASSERT(journal->j_committing_transaction == NULL);
2154 	J_ASSERT(journal->j_checkpoint_transactions == NULL);
2155 	spin_unlock(&journal->j_list_lock);
2156 
2157 	/*
2158 	 * OK, all checkpoint transactions have been checked, now check the
2159 	 * write out io error flag and abort the journal if some buffer failed
2160 	 * to write back to the original location, otherwise the filesystem
2161 	 * may become inconsistent.
2162 	 */
2163 	if (!is_journal_aborted(journal) &&
2164 	    test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags))
2165 		jbd2_journal_abort(journal, -EIO);
2166 
2167 	if (journal->j_sb_buffer) {
2168 		if (!is_journal_aborted(journal)) {
2169 			mutex_lock_io(&journal->j_checkpoint_mutex);
2170 
2171 			write_lock(&journal->j_state_lock);
2172 			journal->j_tail_sequence =
2173 				++journal->j_transaction_sequence;
2174 			write_unlock(&journal->j_state_lock);
2175 
2176 			jbd2_mark_journal_empty(journal,
2177 					REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
2178 			mutex_unlock(&journal->j_checkpoint_mutex);
2179 		} else
2180 			err = -EIO;
2181 		brelse(journal->j_sb_buffer);
2182 	}
2183 
2184 	if (journal->j_shrinker.flags & SHRINKER_REGISTERED) {
2185 		percpu_counter_destroy(&journal->j_checkpoint_jh_count);
2186 		unregister_shrinker(&journal->j_shrinker);
2187 	}
2188 	if (journal->j_proc_entry)
2189 		jbd2_stats_proc_exit(journal);
2190 	iput(journal->j_inode);
2191 	if (journal->j_revoke)
2192 		jbd2_journal_destroy_revoke(journal);
2193 	if (journal->j_chksum_driver)
2194 		crypto_free_shash(journal->j_chksum_driver);
2195 	kfree(journal->j_fc_wbuf);
2196 	kfree(journal->j_wbuf);
2197 	kfree(journal);
2198 
2199 	return err;
2200 }
2201 
2202 
2203 /**
2204  * jbd2_journal_check_used_features() - Check if features specified are used.
2205  * @journal: Journal to check.
2206  * @compat: bitmask of compatible features
2207  * @ro: bitmask of features that force read-only mount
2208  * @incompat: bitmask of incompatible features
2209  *
2210  * Check whether the journal uses all of a given set of
2211  * features.  Return true (non-zero) if it does.
2212  **/
2213 
jbd2_journal_check_used_features(journal_t * journal,unsigned long compat,unsigned long ro,unsigned long incompat)2214 int jbd2_journal_check_used_features(journal_t *journal, unsigned long compat,
2215 				 unsigned long ro, unsigned long incompat)
2216 {
2217 	journal_superblock_t *sb;
2218 
2219 	if (!compat && !ro && !incompat)
2220 		return 1;
2221 	/* Load journal superblock if it is not loaded yet. */
2222 	if (journal->j_format_version == 0 &&
2223 	    journal_get_superblock(journal) != 0)
2224 		return 0;
2225 	if (journal->j_format_version == 1)
2226 		return 0;
2227 
2228 	sb = journal->j_superblock;
2229 
2230 	if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
2231 	    ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
2232 	    ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
2233 		return 1;
2234 
2235 	return 0;
2236 }
2237 
2238 /**
2239  * jbd2_journal_check_available_features() - Check feature set in journalling layer
2240  * @journal: Journal to check.
2241  * @compat: bitmask of compatible features
2242  * @ro: bitmask of features that force read-only mount
2243  * @incompat: bitmask of incompatible features
2244  *
2245  * Check whether the journaling code supports the use of
2246  * all of a given set of features on this journal.  Return true
2247  * (non-zero) if it can. */
2248 
jbd2_journal_check_available_features(journal_t * journal,unsigned long compat,unsigned long ro,unsigned long incompat)2249 int jbd2_journal_check_available_features(journal_t *journal, unsigned long compat,
2250 				      unsigned long ro, unsigned long incompat)
2251 {
2252 	if (!compat && !ro && !incompat)
2253 		return 1;
2254 
2255 	/* We can support any known requested features iff the
2256 	 * superblock is in version 2.  Otherwise we fail to support any
2257 	 * extended sb features. */
2258 
2259 	if (journal->j_format_version != 2)
2260 		return 0;
2261 
2262 	if ((compat   & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
2263 	    (ro       & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
2264 	    (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
2265 		return 1;
2266 
2267 	return 0;
2268 }
2269 
2270 static int
jbd2_journal_initialize_fast_commit(journal_t * journal)2271 jbd2_journal_initialize_fast_commit(journal_t *journal)
2272 {
2273 	journal_superblock_t *sb = journal->j_superblock;
2274 	unsigned long long num_fc_blks;
2275 
2276 	num_fc_blks = jbd2_journal_get_num_fc_blks(sb);
2277 	if (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS)
2278 		return -ENOSPC;
2279 
2280 	/* Are we called twice? */
2281 	WARN_ON(journal->j_fc_wbuf != NULL);
2282 	journal->j_fc_wbuf = kmalloc_array(num_fc_blks,
2283 				sizeof(struct buffer_head *), GFP_KERNEL);
2284 	if (!journal->j_fc_wbuf)
2285 		return -ENOMEM;
2286 
2287 	journal->j_fc_wbufsize = num_fc_blks;
2288 	journal->j_fc_last = journal->j_last;
2289 	journal->j_last = journal->j_fc_last - num_fc_blks;
2290 	journal->j_fc_first = journal->j_last + 1;
2291 	journal->j_fc_off = 0;
2292 	journal->j_free = journal->j_last - journal->j_first;
2293 	journal->j_max_transaction_buffers =
2294 		jbd2_journal_get_max_txn_bufs(journal);
2295 
2296 	return 0;
2297 }
2298 
2299 /**
2300  * jbd2_journal_set_features() - Mark a given journal feature in the superblock
2301  * @journal: Journal to act on.
2302  * @compat: bitmask of compatible features
2303  * @ro: bitmask of features that force read-only mount
2304  * @incompat: bitmask of incompatible features
2305  *
2306  * Mark a given journal feature as present on the
2307  * superblock.  Returns true if the requested features could be set.
2308  *
2309  */
2310 
jbd2_journal_set_features(journal_t * journal,unsigned long compat,unsigned long ro,unsigned long incompat)2311 int jbd2_journal_set_features(journal_t *journal, unsigned long compat,
2312 			  unsigned long ro, unsigned long incompat)
2313 {
2314 #define INCOMPAT_FEATURE_ON(f) \
2315 		((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f)))
2316 #define COMPAT_FEATURE_ON(f) \
2317 		((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f)))
2318 	journal_superblock_t *sb;
2319 
2320 	if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
2321 		return 1;
2322 
2323 	if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
2324 		return 0;
2325 
2326 	/* If enabling v2 checksums, turn on v3 instead */
2327 	if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2) {
2328 		incompat &= ~JBD2_FEATURE_INCOMPAT_CSUM_V2;
2329 		incompat |= JBD2_FEATURE_INCOMPAT_CSUM_V3;
2330 	}
2331 
2332 	/* Asking for checksumming v3 and v1?  Only give them v3. */
2333 	if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V3 &&
2334 	    compat & JBD2_FEATURE_COMPAT_CHECKSUM)
2335 		compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM;
2336 
2337 	jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
2338 		  compat, ro, incompat);
2339 
2340 	sb = journal->j_superblock;
2341 
2342 	if (incompat & JBD2_FEATURE_INCOMPAT_FAST_COMMIT) {
2343 		if (jbd2_journal_initialize_fast_commit(journal)) {
2344 			pr_err("JBD2: Cannot enable fast commits.\n");
2345 			return 0;
2346 		}
2347 	}
2348 
2349 	/* Load the checksum driver if necessary */
2350 	if ((journal->j_chksum_driver == NULL) &&
2351 	    INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
2352 		journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
2353 		if (IS_ERR(journal->j_chksum_driver)) {
2354 			printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
2355 			journal->j_chksum_driver = NULL;
2356 			return 0;
2357 		}
2358 		/* Precompute checksum seed for all metadata */
2359 		journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
2360 						   sizeof(sb->s_uuid));
2361 	}
2362 
2363 	lock_buffer(journal->j_sb_buffer);
2364 
2365 	/* If enabling v3 checksums, update superblock */
2366 	if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
2367 		sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
2368 		sb->s_feature_compat &=
2369 			~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
2370 	}
2371 
2372 	/* If enabling v1 checksums, downgrade superblock */
2373 	if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM))
2374 		sb->s_feature_incompat &=
2375 			~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2 |
2376 				     JBD2_FEATURE_INCOMPAT_CSUM_V3);
2377 
2378 	sb->s_feature_compat    |= cpu_to_be32(compat);
2379 	sb->s_feature_ro_compat |= cpu_to_be32(ro);
2380 	sb->s_feature_incompat  |= cpu_to_be32(incompat);
2381 	unlock_buffer(journal->j_sb_buffer);
2382 	journal->j_revoke_records_per_block =
2383 				journal_revoke_records_per_block(journal);
2384 
2385 	return 1;
2386 #undef COMPAT_FEATURE_ON
2387 #undef INCOMPAT_FEATURE_ON
2388 }
2389 
2390 /*
2391  * jbd2_journal_clear_features() - Clear a given journal feature in the
2392  * 				    superblock
2393  * @journal: Journal to act on.
2394  * @compat: bitmask of compatible features
2395  * @ro: bitmask of features that force read-only mount
2396  * @incompat: bitmask of incompatible features
2397  *
2398  * Clear a given journal feature as present on the
2399  * superblock.
2400  */
jbd2_journal_clear_features(journal_t * journal,unsigned long compat,unsigned long ro,unsigned long incompat)2401 void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
2402 				unsigned long ro, unsigned long incompat)
2403 {
2404 	journal_superblock_t *sb;
2405 
2406 	jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
2407 		  compat, ro, incompat);
2408 
2409 	sb = journal->j_superblock;
2410 
2411 	sb->s_feature_compat    &= ~cpu_to_be32(compat);
2412 	sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
2413 	sb->s_feature_incompat  &= ~cpu_to_be32(incompat);
2414 	journal->j_revoke_records_per_block =
2415 				journal_revoke_records_per_block(journal);
2416 }
2417 EXPORT_SYMBOL(jbd2_journal_clear_features);
2418 
2419 /**
2420  * jbd2_journal_flush() - Flush journal
2421  * @journal: Journal to act on.
2422  * @flags: optional operation on the journal blocks after the flush (see below)
2423  *
2424  * Flush all data for a given journal to disk and empty the journal.
2425  * Filesystems can use this when remounting readonly to ensure that
2426  * recovery does not need to happen on remount. Optionally, a discard or zeroout
2427  * can be issued on the journal blocks after flushing.
2428  *
2429  * flags:
2430  *	JBD2_JOURNAL_FLUSH_DISCARD: issues discards for the journal blocks
2431  *	JBD2_JOURNAL_FLUSH_ZEROOUT: issues zeroouts for the journal blocks
2432  */
jbd2_journal_flush(journal_t * journal,unsigned int flags)2433 int jbd2_journal_flush(journal_t *journal, unsigned int flags)
2434 {
2435 	int err = 0;
2436 	transaction_t *transaction = NULL;
2437 
2438 	write_lock(&journal->j_state_lock);
2439 
2440 	/* Force everything buffered to the log... */
2441 	if (journal->j_running_transaction) {
2442 		transaction = journal->j_running_transaction;
2443 		__jbd2_log_start_commit(journal, transaction->t_tid);
2444 	} else if (journal->j_committing_transaction)
2445 		transaction = journal->j_committing_transaction;
2446 
2447 	/* Wait for the log commit to complete... */
2448 	if (transaction) {
2449 		tid_t tid = transaction->t_tid;
2450 
2451 		write_unlock(&journal->j_state_lock);
2452 		jbd2_log_wait_commit(journal, tid);
2453 	} else {
2454 		write_unlock(&journal->j_state_lock);
2455 	}
2456 
2457 	/* ...and flush everything in the log out to disk. */
2458 	spin_lock(&journal->j_list_lock);
2459 	while (!err && journal->j_checkpoint_transactions != NULL) {
2460 		spin_unlock(&journal->j_list_lock);
2461 		mutex_lock_io(&journal->j_checkpoint_mutex);
2462 		err = jbd2_log_do_checkpoint(journal);
2463 		mutex_unlock(&journal->j_checkpoint_mutex);
2464 		spin_lock(&journal->j_list_lock);
2465 	}
2466 	spin_unlock(&journal->j_list_lock);
2467 
2468 	if (is_journal_aborted(journal))
2469 		return -EIO;
2470 
2471 	mutex_lock_io(&journal->j_checkpoint_mutex);
2472 	if (!err) {
2473 		err = jbd2_cleanup_journal_tail(journal);
2474 		if (err < 0) {
2475 			mutex_unlock(&journal->j_checkpoint_mutex);
2476 			goto out;
2477 		}
2478 		err = 0;
2479 	}
2480 
2481 	/* Finally, mark the journal as really needing no recovery.
2482 	 * This sets s_start==0 in the underlying superblock, which is
2483 	 * the magic code for a fully-recovered superblock.  Any future
2484 	 * commits of data to the journal will restore the current
2485 	 * s_start value. */
2486 	jbd2_mark_journal_empty(journal, REQ_SYNC | REQ_FUA);
2487 
2488 	if (flags)
2489 		err = __jbd2_journal_erase(journal, flags);
2490 
2491 	mutex_unlock(&journal->j_checkpoint_mutex);
2492 	write_lock(&journal->j_state_lock);
2493 	J_ASSERT(!journal->j_running_transaction);
2494 	J_ASSERT(!journal->j_committing_transaction);
2495 	J_ASSERT(!journal->j_checkpoint_transactions);
2496 	J_ASSERT(journal->j_head == journal->j_tail);
2497 	J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
2498 	write_unlock(&journal->j_state_lock);
2499 out:
2500 	return err;
2501 }
2502 
2503 /**
2504  * jbd2_journal_wipe() - Wipe journal contents
2505  * @journal: Journal to act on.
2506  * @write: flag (see below)
2507  *
2508  * Wipe out all of the contents of a journal, safely.  This will produce
2509  * a warning if the journal contains any valid recovery information.
2510  * Must be called between journal_init_*() and jbd2_journal_load().
2511  *
2512  * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
2513  * we merely suppress recovery.
2514  */
2515 
jbd2_journal_wipe(journal_t * journal,int write)2516 int jbd2_journal_wipe(journal_t *journal, int write)
2517 {
2518 	int err = 0;
2519 
2520 	J_ASSERT (!(journal->j_flags & JBD2_LOADED));
2521 
2522 	err = load_superblock(journal);
2523 	if (err)
2524 		return err;
2525 
2526 	if (!journal->j_tail)
2527 		goto no_recovery;
2528 
2529 	printk(KERN_WARNING "JBD2: %s recovery information on journal\n",
2530 		write ? "Clearing" : "Ignoring");
2531 
2532 	err = jbd2_journal_skip_recovery(journal);
2533 	if (write) {
2534 		/* Lock to make assertions happy... */
2535 		mutex_lock_io(&journal->j_checkpoint_mutex);
2536 		jbd2_mark_journal_empty(journal, REQ_SYNC | REQ_FUA);
2537 		mutex_unlock(&journal->j_checkpoint_mutex);
2538 	}
2539 
2540  no_recovery:
2541 	return err;
2542 }
2543 
2544 /**
2545  * jbd2_journal_abort () - Shutdown the journal immediately.
2546  * @journal: the journal to shutdown.
2547  * @errno:   an error number to record in the journal indicating
2548  *           the reason for the shutdown.
2549  *
2550  * Perform a complete, immediate shutdown of the ENTIRE
2551  * journal (not of a single transaction).  This operation cannot be
2552  * undone without closing and reopening the journal.
2553  *
2554  * The jbd2_journal_abort function is intended to support higher level error
2555  * recovery mechanisms such as the ext2/ext3 remount-readonly error
2556  * mode.
2557  *
2558  * Journal abort has very specific semantics.  Any existing dirty,
2559  * unjournaled buffers in the main filesystem will still be written to
2560  * disk by bdflush, but the journaling mechanism will be suspended
2561  * immediately and no further transaction commits will be honoured.
2562  *
2563  * Any dirty, journaled buffers will be written back to disk without
2564  * hitting the journal.  Atomicity cannot be guaranteed on an aborted
2565  * filesystem, but we _do_ attempt to leave as much data as possible
2566  * behind for fsck to use for cleanup.
2567  *
2568  * Any attempt to get a new transaction handle on a journal which is in
2569  * ABORT state will just result in an -EROFS error return.  A
2570  * jbd2_journal_stop on an existing handle will return -EIO if we have
2571  * entered abort state during the update.
2572  *
2573  * Recursive transactions are not disturbed by journal abort until the
2574  * final jbd2_journal_stop, which will receive the -EIO error.
2575  *
2576  * Finally, the jbd2_journal_abort call allows the caller to supply an errno
2577  * which will be recorded (if possible) in the journal superblock.  This
2578  * allows a client to record failure conditions in the middle of a
2579  * transaction without having to complete the transaction to record the
2580  * failure to disk.  ext3_error, for example, now uses this
2581  * functionality.
2582  *
2583  */
2584 
jbd2_journal_abort(journal_t * journal,int errno)2585 void jbd2_journal_abort(journal_t *journal, int errno)
2586 {
2587 	transaction_t *transaction;
2588 
2589 	/*
2590 	 * Lock the aborting procedure until everything is done, this avoid
2591 	 * races between filesystem's error handling flow (e.g. ext4_abort()),
2592 	 * ensure panic after the error info is written into journal's
2593 	 * superblock.
2594 	 */
2595 	mutex_lock(&journal->j_abort_mutex);
2596 	/*
2597 	 * ESHUTDOWN always takes precedence because a file system check
2598 	 * caused by any other journal abort error is not required after
2599 	 * a shutdown triggered.
2600 	 */
2601 	write_lock(&journal->j_state_lock);
2602 	if (journal->j_flags & JBD2_ABORT) {
2603 		int old_errno = journal->j_errno;
2604 
2605 		write_unlock(&journal->j_state_lock);
2606 		if (old_errno != -ESHUTDOWN && errno == -ESHUTDOWN) {
2607 			journal->j_errno = errno;
2608 			jbd2_journal_update_sb_errno(journal);
2609 		}
2610 		mutex_unlock(&journal->j_abort_mutex);
2611 		return;
2612 	}
2613 
2614 	/*
2615 	 * Mark the abort as occurred and start current running transaction
2616 	 * to release all journaled buffer.
2617 	 */
2618 	pr_err("Aborting journal on device %s.\n", journal->j_devname);
2619 
2620 	journal->j_flags |= JBD2_ABORT;
2621 	journal->j_errno = errno;
2622 	transaction = journal->j_running_transaction;
2623 	if (transaction)
2624 		__jbd2_log_start_commit(journal, transaction->t_tid);
2625 	write_unlock(&journal->j_state_lock);
2626 
2627 	/*
2628 	 * Record errno to the journal super block, so that fsck and jbd2
2629 	 * layer could realise that a filesystem check is needed.
2630 	 */
2631 	jbd2_journal_update_sb_errno(journal);
2632 	mutex_unlock(&journal->j_abort_mutex);
2633 }
2634 
2635 /**
2636  * jbd2_journal_errno() - returns the journal's error state.
2637  * @journal: journal to examine.
2638  *
2639  * This is the errno number set with jbd2_journal_abort(), the last
2640  * time the journal was mounted - if the journal was stopped
2641  * without calling abort this will be 0.
2642  *
2643  * If the journal has been aborted on this mount time -EROFS will
2644  * be returned.
2645  */
jbd2_journal_errno(journal_t * journal)2646 int jbd2_journal_errno(journal_t *journal)
2647 {
2648 	int err;
2649 
2650 	read_lock(&journal->j_state_lock);
2651 	if (journal->j_flags & JBD2_ABORT)
2652 		err = -EROFS;
2653 	else
2654 		err = journal->j_errno;
2655 	read_unlock(&journal->j_state_lock);
2656 	return err;
2657 }
2658 
2659 /**
2660  * jbd2_journal_clear_err() - clears the journal's error state
2661  * @journal: journal to act on.
2662  *
2663  * An error must be cleared or acked to take a FS out of readonly
2664  * mode.
2665  */
jbd2_journal_clear_err(journal_t * journal)2666 int jbd2_journal_clear_err(journal_t *journal)
2667 {
2668 	int err = 0;
2669 
2670 	write_lock(&journal->j_state_lock);
2671 	if (journal->j_flags & JBD2_ABORT)
2672 		err = -EROFS;
2673 	else
2674 		journal->j_errno = 0;
2675 	write_unlock(&journal->j_state_lock);
2676 	return err;
2677 }
2678 
2679 /**
2680  * jbd2_journal_ack_err() - Ack journal err.
2681  * @journal: journal to act on.
2682  *
2683  * An error must be cleared or acked to take a FS out of readonly
2684  * mode.
2685  */
jbd2_journal_ack_err(journal_t * journal)2686 void jbd2_journal_ack_err(journal_t *journal)
2687 {
2688 	write_lock(&journal->j_state_lock);
2689 	if (journal->j_errno)
2690 		journal->j_flags |= JBD2_ACK_ERR;
2691 	write_unlock(&journal->j_state_lock);
2692 }
2693 
jbd2_journal_blocks_per_page(struct inode * inode)2694 int jbd2_journal_blocks_per_page(struct inode *inode)
2695 {
2696 	return 1 << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
2697 }
2698 
2699 /*
2700  * helper functions to deal with 32 or 64bit block numbers.
2701  */
journal_tag_bytes(journal_t * journal)2702 size_t journal_tag_bytes(journal_t *journal)
2703 {
2704 	size_t sz;
2705 
2706 	if (jbd2_has_feature_csum3(journal))
2707 		return sizeof(journal_block_tag3_t);
2708 
2709 	sz = sizeof(journal_block_tag_t);
2710 
2711 	if (jbd2_has_feature_csum2(journal))
2712 		sz += sizeof(__u16);
2713 
2714 	if (jbd2_has_feature_64bit(journal))
2715 		return sz;
2716 	else
2717 		return sz - sizeof(__u32);
2718 }
2719 
2720 /*
2721  * JBD memory management
2722  *
2723  * These functions are used to allocate block-sized chunks of memory
2724  * used for making copies of buffer_head data.  Very often it will be
2725  * page-sized chunks of data, but sometimes it will be in
2726  * sub-page-size chunks.  (For example, 16k pages on Power systems
2727  * with a 4k block file system.)  For blocks smaller than a page, we
2728  * use a SLAB allocator.  There are slab caches for each block size,
2729  * which are allocated at mount time, if necessary, and we only free
2730  * (all of) the slab caches when/if the jbd2 module is unloaded.  For
2731  * this reason we don't need to a mutex to protect access to
2732  * jbd2_slab[] allocating or releasing memory; only in
2733  * jbd2_journal_create_slab().
2734  */
2735 #define JBD2_MAX_SLABS 8
2736 static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
2737 
2738 static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
2739 	"jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
2740 	"jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
2741 };
2742 
2743 
jbd2_journal_destroy_slabs(void)2744 static void jbd2_journal_destroy_slabs(void)
2745 {
2746 	int i;
2747 
2748 	for (i = 0; i < JBD2_MAX_SLABS; i++) {
2749 		kmem_cache_destroy(jbd2_slab[i]);
2750 		jbd2_slab[i] = NULL;
2751 	}
2752 }
2753 
jbd2_journal_create_slab(size_t size)2754 static int jbd2_journal_create_slab(size_t size)
2755 {
2756 	static DEFINE_MUTEX(jbd2_slab_create_mutex);
2757 	int i = order_base_2(size) - 10;
2758 	size_t slab_size;
2759 
2760 	if (size == PAGE_SIZE)
2761 		return 0;
2762 
2763 	if (i >= JBD2_MAX_SLABS)
2764 		return -EINVAL;
2765 
2766 	if (unlikely(i < 0))
2767 		i = 0;
2768 	mutex_lock(&jbd2_slab_create_mutex);
2769 	if (jbd2_slab[i]) {
2770 		mutex_unlock(&jbd2_slab_create_mutex);
2771 		return 0;	/* Already created */
2772 	}
2773 
2774 	slab_size = 1 << (i+10);
2775 	jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
2776 					 slab_size, 0, NULL);
2777 	mutex_unlock(&jbd2_slab_create_mutex);
2778 	if (!jbd2_slab[i]) {
2779 		printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
2780 		return -ENOMEM;
2781 	}
2782 	return 0;
2783 }
2784 
get_slab(size_t size)2785 static struct kmem_cache *get_slab(size_t size)
2786 {
2787 	int i = order_base_2(size) - 10;
2788 
2789 	BUG_ON(i >= JBD2_MAX_SLABS);
2790 	if (unlikely(i < 0))
2791 		i = 0;
2792 	BUG_ON(jbd2_slab[i] == NULL);
2793 	return jbd2_slab[i];
2794 }
2795 
jbd2_alloc(size_t size,gfp_t flags)2796 void *jbd2_alloc(size_t size, gfp_t flags)
2797 {
2798 	void *ptr;
2799 
2800 	BUG_ON(size & (size-1)); /* Must be a power of 2 */
2801 
2802 	if (size < PAGE_SIZE)
2803 		ptr = kmem_cache_alloc(get_slab(size), flags);
2804 	else
2805 		ptr = (void *)__get_free_pages(flags, get_order(size));
2806 
2807 	/* Check alignment; SLUB has gotten this wrong in the past,
2808 	 * and this can lead to user data corruption! */
2809 	BUG_ON(((unsigned long) ptr) & (size-1));
2810 
2811 	return ptr;
2812 }
2813 
jbd2_free(void * ptr,size_t size)2814 void jbd2_free(void *ptr, size_t size)
2815 {
2816 	if (size < PAGE_SIZE)
2817 		kmem_cache_free(get_slab(size), ptr);
2818 	else
2819 		free_pages((unsigned long)ptr, get_order(size));
2820 };
2821 
2822 /*
2823  * Journal_head storage management
2824  */
2825 static struct kmem_cache *jbd2_journal_head_cache;
2826 #ifdef CONFIG_JBD2_DEBUG
2827 static atomic_t nr_journal_heads = ATOMIC_INIT(0);
2828 #endif
2829 
jbd2_journal_init_journal_head_cache(void)2830 static int __init jbd2_journal_init_journal_head_cache(void)
2831 {
2832 	J_ASSERT(!jbd2_journal_head_cache);
2833 	jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
2834 				sizeof(struct journal_head),
2835 				0,		/* offset */
2836 				SLAB_TEMPORARY | SLAB_TYPESAFE_BY_RCU,
2837 				NULL);		/* ctor */
2838 	if (!jbd2_journal_head_cache) {
2839 		printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
2840 		return -ENOMEM;
2841 	}
2842 	return 0;
2843 }
2844 
jbd2_journal_destroy_journal_head_cache(void)2845 static void jbd2_journal_destroy_journal_head_cache(void)
2846 {
2847 	kmem_cache_destroy(jbd2_journal_head_cache);
2848 	jbd2_journal_head_cache = NULL;
2849 }
2850 
2851 /*
2852  * journal_head splicing and dicing
2853  */
journal_alloc_journal_head(void)2854 static struct journal_head *journal_alloc_journal_head(void)
2855 {
2856 	struct journal_head *ret;
2857 
2858 #ifdef CONFIG_JBD2_DEBUG
2859 	atomic_inc(&nr_journal_heads);
2860 #endif
2861 	ret = kmem_cache_zalloc(jbd2_journal_head_cache, GFP_NOFS);
2862 	if (!ret) {
2863 		jbd_debug(1, "out of memory for journal_head\n");
2864 		pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__);
2865 		ret = kmem_cache_zalloc(jbd2_journal_head_cache,
2866 				GFP_NOFS | __GFP_NOFAIL);
2867 	}
2868 	if (ret)
2869 		spin_lock_init(&ret->b_state_lock);
2870 	return ret;
2871 }
2872 
journal_free_journal_head(struct journal_head * jh)2873 static void journal_free_journal_head(struct journal_head *jh)
2874 {
2875 #ifdef CONFIG_JBD2_DEBUG
2876 	atomic_dec(&nr_journal_heads);
2877 	memset(jh, JBD2_POISON_FREE, sizeof(*jh));
2878 #endif
2879 	kmem_cache_free(jbd2_journal_head_cache, jh);
2880 }
2881 
2882 /*
2883  * A journal_head is attached to a buffer_head whenever JBD has an
2884  * interest in the buffer.
2885  *
2886  * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
2887  * is set.  This bit is tested in core kernel code where we need to take
2888  * JBD-specific actions.  Testing the zeroness of ->b_private is not reliable
2889  * there.
2890  *
2891  * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
2892  *
2893  * When a buffer has its BH_JBD bit set it is immune from being released by
2894  * core kernel code, mainly via ->b_count.
2895  *
2896  * A journal_head is detached from its buffer_head when the journal_head's
2897  * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
2898  * transaction (b_cp_transaction) hold their references to b_jcount.
2899  *
2900  * Various places in the kernel want to attach a journal_head to a buffer_head
2901  * _before_ attaching the journal_head to a transaction.  To protect the
2902  * journal_head in this situation, jbd2_journal_add_journal_head elevates the
2903  * journal_head's b_jcount refcount by one.  The caller must call
2904  * jbd2_journal_put_journal_head() to undo this.
2905  *
2906  * So the typical usage would be:
2907  *
2908  *	(Attach a journal_head if needed.  Increments b_jcount)
2909  *	struct journal_head *jh = jbd2_journal_add_journal_head(bh);
2910  *	...
2911  *      (Get another reference for transaction)
2912  *	jbd2_journal_grab_journal_head(bh);
2913  *	jh->b_transaction = xxx;
2914  *	(Put original reference)
2915  *	jbd2_journal_put_journal_head(jh);
2916  */
2917 
2918 /*
2919  * Give a buffer_head a journal_head.
2920  *
2921  * May sleep.
2922  */
jbd2_journal_add_journal_head(struct buffer_head * bh)2923 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
2924 {
2925 	struct journal_head *jh;
2926 	struct journal_head *new_jh = NULL;
2927 
2928 repeat:
2929 	if (!buffer_jbd(bh))
2930 		new_jh = journal_alloc_journal_head();
2931 
2932 	jbd_lock_bh_journal_head(bh);
2933 	if (buffer_jbd(bh)) {
2934 		jh = bh2jh(bh);
2935 	} else {
2936 		J_ASSERT_BH(bh,
2937 			(atomic_read(&bh->b_count) > 0) ||
2938 			(bh->b_page && bh->b_page->mapping));
2939 
2940 		if (!new_jh) {
2941 			jbd_unlock_bh_journal_head(bh);
2942 			goto repeat;
2943 		}
2944 
2945 		jh = new_jh;
2946 		new_jh = NULL;		/* We consumed it */
2947 		set_buffer_jbd(bh);
2948 		bh->b_private = jh;
2949 		jh->b_bh = bh;
2950 		get_bh(bh);
2951 		BUFFER_TRACE(bh, "added journal_head");
2952 	}
2953 	jh->b_jcount++;
2954 	jbd_unlock_bh_journal_head(bh);
2955 	if (new_jh)
2956 		journal_free_journal_head(new_jh);
2957 	return bh->b_private;
2958 }
2959 
2960 /*
2961  * Grab a ref against this buffer_head's journal_head.  If it ended up not
2962  * having a journal_head, return NULL
2963  */
jbd2_journal_grab_journal_head(struct buffer_head * bh)2964 struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
2965 {
2966 	struct journal_head *jh = NULL;
2967 
2968 	jbd_lock_bh_journal_head(bh);
2969 	if (buffer_jbd(bh)) {
2970 		jh = bh2jh(bh);
2971 		jh->b_jcount++;
2972 	}
2973 	jbd_unlock_bh_journal_head(bh);
2974 	return jh;
2975 }
2976 EXPORT_SYMBOL(jbd2_journal_grab_journal_head);
2977 
__journal_remove_journal_head(struct buffer_head * bh)2978 static void __journal_remove_journal_head(struct buffer_head *bh)
2979 {
2980 	struct journal_head *jh = bh2jh(bh);
2981 
2982 	J_ASSERT_JH(jh, jh->b_transaction == NULL);
2983 	J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
2984 	J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
2985 	J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
2986 	J_ASSERT_BH(bh, buffer_jbd(bh));
2987 	J_ASSERT_BH(bh, jh2bh(jh) == bh);
2988 	BUFFER_TRACE(bh, "remove journal_head");
2989 
2990 	/* Unlink before dropping the lock */
2991 	bh->b_private = NULL;
2992 	jh->b_bh = NULL;	/* debug, really */
2993 	clear_buffer_jbd(bh);
2994 }
2995 
journal_release_journal_head(struct journal_head * jh,size_t b_size)2996 static void journal_release_journal_head(struct journal_head *jh, size_t b_size)
2997 {
2998 	if (jh->b_frozen_data) {
2999 		printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
3000 		jbd2_free(jh->b_frozen_data, b_size);
3001 	}
3002 	if (jh->b_committed_data) {
3003 		printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
3004 		jbd2_free(jh->b_committed_data, b_size);
3005 	}
3006 	journal_free_journal_head(jh);
3007 }
3008 
3009 /*
3010  * Drop a reference on the passed journal_head.  If it fell to zero then
3011  * release the journal_head from the buffer_head.
3012  */
jbd2_journal_put_journal_head(struct journal_head * jh)3013 void jbd2_journal_put_journal_head(struct journal_head *jh)
3014 {
3015 	struct buffer_head *bh = jh2bh(jh);
3016 
3017 	jbd_lock_bh_journal_head(bh);
3018 	J_ASSERT_JH(jh, jh->b_jcount > 0);
3019 	--jh->b_jcount;
3020 	if (!jh->b_jcount) {
3021 		__journal_remove_journal_head(bh);
3022 		jbd_unlock_bh_journal_head(bh);
3023 		journal_release_journal_head(jh, bh->b_size);
3024 		__brelse(bh);
3025 	} else {
3026 		jbd_unlock_bh_journal_head(bh);
3027 	}
3028 }
3029 EXPORT_SYMBOL(jbd2_journal_put_journal_head);
3030 
3031 /*
3032  * Initialize jbd inode head
3033  */
jbd2_journal_init_jbd_inode(struct jbd2_inode * jinode,struct inode * inode)3034 void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
3035 {
3036 	jinode->i_transaction = NULL;
3037 	jinode->i_next_transaction = NULL;
3038 	jinode->i_vfs_inode = inode;
3039 	jinode->i_flags = 0;
3040 	jinode->i_dirty_start = 0;
3041 	jinode->i_dirty_end = 0;
3042 	INIT_LIST_HEAD(&jinode->i_list);
3043 }
3044 
3045 /*
3046  * Function to be called before we start removing inode from memory (i.e.,
3047  * clear_inode() is a fine place to be called from). It removes inode from
3048  * transaction's lists.
3049  */
jbd2_journal_release_jbd_inode(journal_t * journal,struct jbd2_inode * jinode)3050 void jbd2_journal_release_jbd_inode(journal_t *journal,
3051 				    struct jbd2_inode *jinode)
3052 {
3053 	if (!journal)
3054 		return;
3055 restart:
3056 	spin_lock(&journal->j_list_lock);
3057 	/* Is commit writing out inode - we have to wait */
3058 	if (jinode->i_flags & JI_COMMIT_RUNNING) {
3059 		wait_queue_head_t *wq;
3060 		DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
3061 		wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
3062 		prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
3063 		spin_unlock(&journal->j_list_lock);
3064 		schedule();
3065 		finish_wait(wq, &wait.wq_entry);
3066 		goto restart;
3067 	}
3068 
3069 	if (jinode->i_transaction) {
3070 		list_del(&jinode->i_list);
3071 		jinode->i_transaction = NULL;
3072 	}
3073 	spin_unlock(&journal->j_list_lock);
3074 }
3075 
3076 
3077 #ifdef CONFIG_PROC_FS
3078 
3079 #define JBD2_STATS_PROC_NAME "fs/jbd2"
3080 
jbd2_create_jbd_stats_proc_entry(void)3081 static void __init jbd2_create_jbd_stats_proc_entry(void)
3082 {
3083 	proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
3084 }
3085 
jbd2_remove_jbd_stats_proc_entry(void)3086 static void __exit jbd2_remove_jbd_stats_proc_entry(void)
3087 {
3088 	if (proc_jbd2_stats)
3089 		remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
3090 }
3091 
3092 #else
3093 
3094 #define jbd2_create_jbd_stats_proc_entry() do {} while (0)
3095 #define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
3096 
3097 #endif
3098 
3099 struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
3100 
jbd2_journal_init_inode_cache(void)3101 static int __init jbd2_journal_init_inode_cache(void)
3102 {
3103 	J_ASSERT(!jbd2_inode_cache);
3104 	jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
3105 	if (!jbd2_inode_cache) {
3106 		pr_emerg("JBD2: failed to create inode cache\n");
3107 		return -ENOMEM;
3108 	}
3109 	return 0;
3110 }
3111 
jbd2_journal_init_handle_cache(void)3112 static int __init jbd2_journal_init_handle_cache(void)
3113 {
3114 	J_ASSERT(!jbd2_handle_cache);
3115 	jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
3116 	if (!jbd2_handle_cache) {
3117 		printk(KERN_EMERG "JBD2: failed to create handle cache\n");
3118 		return -ENOMEM;
3119 	}
3120 	return 0;
3121 }
3122 
jbd2_journal_destroy_inode_cache(void)3123 static void jbd2_journal_destroy_inode_cache(void)
3124 {
3125 	kmem_cache_destroy(jbd2_inode_cache);
3126 	jbd2_inode_cache = NULL;
3127 }
3128 
jbd2_journal_destroy_handle_cache(void)3129 static void jbd2_journal_destroy_handle_cache(void)
3130 {
3131 	kmem_cache_destroy(jbd2_handle_cache);
3132 	jbd2_handle_cache = NULL;
3133 }
3134 
3135 /*
3136  * Module startup and shutdown
3137  */
3138 
journal_init_caches(void)3139 static int __init journal_init_caches(void)
3140 {
3141 	int ret;
3142 
3143 	ret = jbd2_journal_init_revoke_record_cache();
3144 	if (ret == 0)
3145 		ret = jbd2_journal_init_revoke_table_cache();
3146 	if (ret == 0)
3147 		ret = jbd2_journal_init_journal_head_cache();
3148 	if (ret == 0)
3149 		ret = jbd2_journal_init_handle_cache();
3150 	if (ret == 0)
3151 		ret = jbd2_journal_init_inode_cache();
3152 	if (ret == 0)
3153 		ret = jbd2_journal_init_transaction_cache();
3154 	return ret;
3155 }
3156 
jbd2_journal_destroy_caches(void)3157 static void jbd2_journal_destroy_caches(void)
3158 {
3159 	jbd2_journal_destroy_revoke_record_cache();
3160 	jbd2_journal_destroy_revoke_table_cache();
3161 	jbd2_journal_destroy_journal_head_cache();
3162 	jbd2_journal_destroy_handle_cache();
3163 	jbd2_journal_destroy_inode_cache();
3164 	jbd2_journal_destroy_transaction_cache();
3165 	jbd2_journal_destroy_slabs();
3166 }
3167 
journal_init(void)3168 static int __init journal_init(void)
3169 {
3170 	int ret;
3171 
3172 	BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
3173 
3174 	ret = journal_init_caches();
3175 	if (ret == 0) {
3176 		jbd2_create_jbd_stats_proc_entry();
3177 	} else {
3178 		jbd2_journal_destroy_caches();
3179 	}
3180 	return ret;
3181 }
3182 
journal_exit(void)3183 static void __exit journal_exit(void)
3184 {
3185 #ifdef CONFIG_JBD2_DEBUG
3186 	int n = atomic_read(&nr_journal_heads);
3187 	if (n)
3188 		printk(KERN_ERR "JBD2: leaked %d journal_heads!\n", n);
3189 #endif
3190 	jbd2_remove_jbd_stats_proc_entry();
3191 	jbd2_journal_destroy_caches();
3192 }
3193 
3194 MODULE_LICENSE("GPL");
3195 module_init(journal_init);
3196 module_exit(journal_exit);
3197 
3198