Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0+
2 : /*
3 : * linux/fs/jbd2/checkpoint.c
4 : *
5 : * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
6 : *
7 : * Copyright 1999 Red Hat Software --- All Rights Reserved
8 : *
9 : * Checkpoint routines for the generic filesystem journaling code.
10 : * Part of the ext2fs journaling system.
11 : *
12 : * Checkpointing is the process of ensuring that a section of the log is
13 : * committed fully to disk, so that that portion of the log can be
14 : * reused.
15 : */
16 :
17 : #include <linux/time.h>
18 : #include <linux/fs.h>
19 : #include <linux/jbd2.h>
20 : #include <linux/errno.h>
21 : #include <linux/slab.h>
22 : #include <linux/blkdev.h>
23 : #include <trace/events/jbd2.h>
24 :
25 : /*
26 : * Unlink a buffer from a transaction checkpoint list.
27 : *
28 : * Called with j_list_lock held.
29 : */
30 1589 : static inline void __buffer_unlink_first(struct journal_head *jh)
31 : {
32 1589 : transaction_t *transaction = jh->b_cp_transaction;
33 :
34 1589 : jh->b_cpnext->b_cpprev = jh->b_cpprev;
35 1589 : jh->b_cpprev->b_cpnext = jh->b_cpnext;
36 1589 : if (transaction->t_checkpoint_list == jh) {
37 708 : transaction->t_checkpoint_list = jh->b_cpnext;
38 708 : if (transaction->t_checkpoint_list == jh)
39 51 : transaction->t_checkpoint_list = NULL;
40 : }
41 1589 : }
42 :
43 : /*
44 : * Unlink a buffer from a transaction checkpoint(io) list.
45 : *
46 : * Called with j_list_lock held.
47 : */
48 1589 : static inline void __buffer_unlink(struct journal_head *jh)
49 : {
50 1589 : transaction_t *transaction = jh->b_cp_transaction;
51 :
52 1589 : __buffer_unlink_first(jh);
53 1589 : if (transaction->t_checkpoint_io_list == jh) {
54 0 : transaction->t_checkpoint_io_list = jh->b_cpnext;
55 0 : if (transaction->t_checkpoint_io_list == jh)
56 0 : transaction->t_checkpoint_io_list = NULL;
57 : }
58 1589 : }
59 :
60 : /*
61 : * Move a buffer from the checkpoint list to the checkpoint io list
62 : *
63 : * Called with j_list_lock held
64 : */
65 0 : static inline void __buffer_relink_io(struct journal_head *jh)
66 : {
67 0 : transaction_t *transaction = jh->b_cp_transaction;
68 :
69 0 : __buffer_unlink_first(jh);
70 :
71 0 : if (!transaction->t_checkpoint_io_list) {
72 0 : jh->b_cpnext = jh->b_cpprev = jh;
73 : } else {
74 0 : jh->b_cpnext = transaction->t_checkpoint_io_list;
75 0 : jh->b_cpprev = transaction->t_checkpoint_io_list->b_cpprev;
76 0 : jh->b_cpprev->b_cpnext = jh;
77 0 : jh->b_cpnext->b_cpprev = jh;
78 : }
79 0 : transaction->t_checkpoint_io_list = jh;
80 0 : }
81 :
82 : /*
83 : * Try to release a checkpointed buffer from its transaction.
84 : * Returns 1 if we released it and 2 if we also released the
85 : * whole transaction.
86 : *
87 : * Requires j_list_lock
88 : */
89 713 : static int __try_to_free_cp_buf(struct journal_head *jh)
90 : {
91 713 : int ret = 0;
92 713 : struct buffer_head *bh = jh2bh(jh);
93 :
94 1421 : if (jh->b_transaction == NULL && !buffer_locked(bh) &&
95 1364 : !buffer_dirty(bh) && !buffer_write_io_error(bh)) {
96 656 : JBUFFER_TRACE(jh, "remove from checkpoint list");
97 656 : ret = __jbd2_journal_remove_checkpoint(jh) + 1;
98 : }
99 713 : return ret;
100 : }
101 :
102 : /*
103 : * __jbd2_log_wait_for_space: wait until there is space in the journal.
104 : *
105 : * Called under j-state_lock *only*. It will be unlocked if we have to wait
106 : * for a checkpoint to free up some space in the log.
107 : */
108 0 : void __jbd2_log_wait_for_space(journal_t *journal)
109 : __acquires(&journal->j_state_lock)
110 : __releases(&journal->j_state_lock)
111 : {
112 0 : int nblocks, space_left;
113 : /* assert_spin_locked(&journal->j_state_lock); */
114 :
115 0 : nblocks = journal->j_max_transaction_buffers;
116 0 : while (jbd2_log_space_left(journal) < nblocks) {
117 0 : write_unlock(&journal->j_state_lock);
118 0 : mutex_lock_io(&journal->j_checkpoint_mutex);
119 :
120 : /*
121 : * Test again, another process may have checkpointed while we
122 : * were waiting for the checkpoint lock. If there are no
123 : * transactions ready to be checkpointed, try to recover
124 : * journal space by calling cleanup_journal_tail(), and if
125 : * that doesn't work, by waiting for the currently committing
126 : * transaction to complete. If there is absolutely no way
127 : * to make progress, this is either a BUG or corrupted
128 : * filesystem, so abort the journal and leave a stack
129 : * trace for forensic evidence.
130 : */
131 0 : write_lock(&journal->j_state_lock);
132 0 : if (journal->j_flags & JBD2_ABORT) {
133 0 : mutex_unlock(&journal->j_checkpoint_mutex);
134 0 : return;
135 : }
136 0 : spin_lock(&journal->j_list_lock);
137 0 : space_left = jbd2_log_space_left(journal);
138 0 : if (space_left < nblocks) {
139 0 : int chkpt = journal->j_checkpoint_transactions != NULL;
140 0 : tid_t tid = 0;
141 :
142 0 : if (journal->j_committing_transaction)
143 0 : tid = journal->j_committing_transaction->t_tid;
144 0 : spin_unlock(&journal->j_list_lock);
145 0 : write_unlock(&journal->j_state_lock);
146 0 : if (chkpt) {
147 0 : jbd2_log_do_checkpoint(journal);
148 0 : } else if (jbd2_cleanup_journal_tail(journal) == 0) {
149 : /* We were able to recover space; yay! */
150 : ;
151 0 : } else if (tid) {
152 : /*
153 : * jbd2_journal_commit_transaction() may want
154 : * to take the checkpoint_mutex if JBD2_FLUSHED
155 : * is set. So we need to temporarily drop it.
156 : */
157 0 : mutex_unlock(&journal->j_checkpoint_mutex);
158 0 : jbd2_log_wait_commit(journal, tid);
159 0 : write_lock(&journal->j_state_lock);
160 0 : continue;
161 : } else {
162 0 : printk(KERN_ERR "%s: needed %d blocks and "
163 : "only had %d space available\n",
164 : __func__, nblocks, space_left);
165 0 : printk(KERN_ERR "%s: no way to get more "
166 : "journal space in %s\n", __func__,
167 0 : journal->j_devname);
168 0 : WARN_ON(1);
169 0 : jbd2_journal_abort(journal, -EIO);
170 : }
171 0 : write_lock(&journal->j_state_lock);
172 : } else {
173 0 : spin_unlock(&journal->j_list_lock);
174 : }
175 0 : mutex_unlock(&journal->j_checkpoint_mutex);
176 : }
177 : }
178 :
179 : static void
180 0 : __flush_batch(journal_t *journal, int *batch_count)
181 : {
182 0 : int i;
183 0 : struct blk_plug plug;
184 :
185 0 : blk_start_plug(&plug);
186 0 : for (i = 0; i < *batch_count; i++)
187 0 : write_dirty_buffer(journal->j_chkpt_bhs[i], REQ_SYNC);
188 0 : blk_finish_plug(&plug);
189 :
190 0 : for (i = 0; i < *batch_count; i++) {
191 0 : struct buffer_head *bh = journal->j_chkpt_bhs[i];
192 0 : BUFFER_TRACE(bh, "brelse");
193 0 : __brelse(bh);
194 : }
195 0 : *batch_count = 0;
196 0 : }
197 :
198 : /*
199 : * Perform an actual checkpoint. We take the first transaction on the
200 : * list of transactions to be checkpointed and send all its buffers
201 : * to disk. We submit larger chunks of data at once.
202 : *
203 : * The journal should be locked before calling this function.
204 : * Called with j_checkpoint_mutex held.
205 : */
206 0 : int jbd2_log_do_checkpoint(journal_t *journal)
207 : {
208 0 : struct journal_head *jh;
209 0 : struct buffer_head *bh;
210 0 : transaction_t *transaction;
211 0 : tid_t this_tid;
212 0 : int result, batch_count = 0;
213 :
214 0 : jbd_debug(1, "Start checkpoint\n");
215 :
216 : /*
217 : * First thing: if there are any transactions in the log which
218 : * don't need checkpointing, just eliminate them from the
219 : * journal straight away.
220 : */
221 0 : result = jbd2_cleanup_journal_tail(journal);
222 0 : trace_jbd2_checkpoint(journal, result);
223 0 : jbd_debug(1, "cleanup_journal_tail returned %d\n", result);
224 0 : if (result <= 0)
225 : return result;
226 :
227 : /*
228 : * OK, we need to start writing disk blocks. Take one transaction
229 : * and write it.
230 : */
231 0 : result = 0;
232 0 : spin_lock(&journal->j_list_lock);
233 0 : if (!journal->j_checkpoint_transactions)
234 0 : goto out;
235 0 : transaction = journal->j_checkpoint_transactions;
236 0 : if (transaction->t_chp_stats.cs_chp_time == 0)
237 0 : transaction->t_chp_stats.cs_chp_time = jiffies;
238 0 : this_tid = transaction->t_tid;
239 : restart:
240 : /*
241 : * If someone cleaned up this transaction while we slept, we're
242 : * done (maybe it's a new transaction, but it fell at the same
243 : * address).
244 : */
245 0 : if (journal->j_checkpoint_transactions != transaction ||
246 0 : transaction->t_tid != this_tid)
247 0 : goto out;
248 :
249 : /* checkpoint all of the transaction's buffers */
250 0 : while (transaction->t_checkpoint_list) {
251 0 : jh = transaction->t_checkpoint_list;
252 0 : bh = jh2bh(jh);
253 :
254 0 : if (buffer_locked(bh)) {
255 0 : get_bh(bh);
256 0 : spin_unlock(&journal->j_list_lock);
257 0 : wait_on_buffer(bh);
258 : /* the journal_head may have gone by now */
259 0 : BUFFER_TRACE(bh, "brelse");
260 0 : __brelse(bh);
261 0 : goto retry;
262 : }
263 0 : if (jh->b_transaction != NULL) {
264 0 : transaction_t *t = jh->b_transaction;
265 0 : tid_t tid = t->t_tid;
266 :
267 0 : transaction->t_chp_stats.cs_forced_to_close++;
268 0 : spin_unlock(&journal->j_list_lock);
269 0 : if (unlikely(journal->j_flags & JBD2_UNMOUNT))
270 : /*
271 : * The journal thread is dead; so
272 : * starting and waiting for a commit
273 : * to finish will cause us to wait for
274 : * a _very_ long time.
275 : */
276 0 : printk(KERN_ERR
277 : "JBD2: %s: Waiting for Godot: block %llu\n",
278 0 : journal->j_devname, (unsigned long long) bh->b_blocknr);
279 :
280 0 : if (batch_count)
281 0 : __flush_batch(journal, &batch_count);
282 0 : jbd2_log_start_commit(journal, tid);
283 : /*
284 : * jbd2_journal_commit_transaction() may want
285 : * to take the checkpoint_mutex if JBD2_FLUSHED
286 : * is set, jbd2_update_log_tail() called by
287 : * jbd2_journal_commit_transaction() may also take
288 : * checkpoint_mutex. So we need to temporarily
289 : * drop it.
290 : */
291 0 : mutex_unlock(&journal->j_checkpoint_mutex);
292 0 : jbd2_log_wait_commit(journal, tid);
293 0 : mutex_lock_io(&journal->j_checkpoint_mutex);
294 0 : spin_lock(&journal->j_list_lock);
295 0 : goto restart;
296 : }
297 0 : if (!buffer_dirty(bh)) {
298 0 : if (unlikely(buffer_write_io_error(bh)) && !result)
299 0 : result = -EIO;
300 0 : BUFFER_TRACE(bh, "remove from checkpoint");
301 0 : if (__jbd2_journal_remove_checkpoint(jh))
302 : /* The transaction was released; we're done */
303 0 : goto out;
304 0 : continue;
305 : }
306 : /*
307 : * Important: we are about to write the buffer, and
308 : * possibly block, while still holding the journal
309 : * lock. We cannot afford to let the transaction
310 : * logic start messing around with this buffer before
311 : * we write it to disk, as that would break
312 : * recoverability.
313 : */
314 0 : BUFFER_TRACE(bh, "queue");
315 0 : get_bh(bh);
316 0 : J_ASSERT_BH(bh, !buffer_jwrite(bh));
317 0 : journal->j_chkpt_bhs[batch_count++] = bh;
318 0 : __buffer_relink_io(jh);
319 0 : transaction->t_chp_stats.cs_written++;
320 0 : if ((batch_count == JBD2_NR_BATCH) ||
321 0 : need_resched() ||
322 0 : spin_needbreak(&journal->j_list_lock))
323 0 : goto unlock_and_flush;
324 : }
325 :
326 0 : if (batch_count) {
327 0 : unlock_and_flush:
328 0 : spin_unlock(&journal->j_list_lock);
329 0 : retry:
330 0 : if (batch_count)
331 0 : __flush_batch(journal, &batch_count);
332 0 : spin_lock(&journal->j_list_lock);
333 0 : goto restart;
334 : }
335 :
336 : /*
337 : * Now we issued all of the transaction's buffers, let's deal
338 : * with the buffers that are out for I/O.
339 : */
340 0 : restart2:
341 : /* Did somebody clean up the transaction in the meanwhile? */
342 0 : if (journal->j_checkpoint_transactions != transaction ||
343 0 : transaction->t_tid != this_tid)
344 0 : goto out;
345 :
346 0 : while (transaction->t_checkpoint_io_list) {
347 0 : jh = transaction->t_checkpoint_io_list;
348 0 : bh = jh2bh(jh);
349 0 : if (buffer_locked(bh)) {
350 0 : get_bh(bh);
351 0 : spin_unlock(&journal->j_list_lock);
352 0 : wait_on_buffer(bh);
353 : /* the journal_head may have gone by now */
354 0 : BUFFER_TRACE(bh, "brelse");
355 0 : __brelse(bh);
356 0 : spin_lock(&journal->j_list_lock);
357 0 : goto restart2;
358 : }
359 0 : if (unlikely(buffer_write_io_error(bh)) && !result)
360 0 : result = -EIO;
361 :
362 : /*
363 : * Now in whatever state the buffer currently is, we
364 : * know that it has been written out and so we can
365 : * drop it from the list
366 : */
367 0 : if (__jbd2_journal_remove_checkpoint(jh))
368 : break;
369 : }
370 0 : out:
371 0 : spin_unlock(&journal->j_list_lock);
372 0 : if (result < 0)
373 0 : jbd2_journal_abort(journal, result);
374 : else
375 0 : result = jbd2_cleanup_journal_tail(journal);
376 :
377 0 : return (result < 0) ? result : 0;
378 : }
379 :
380 : /*
381 : * Check the list of checkpoint transactions for the journal to see if
382 : * we have already got rid of any since the last update of the log tail
383 : * in the journal superblock. If so, we can instantly roll the
384 : * superblock forward to remove those transactions from the log.
385 : *
386 : * Return <0 on error, 0 on success, 1 if there was nothing to clean up.
387 : *
388 : * Called with the journal lock held.
389 : *
390 : * This is the only part of the journaling code which really needs to be
391 : * aware of transaction aborts. Checkpointing involves writing to the
392 : * main filesystem area rather than to the journal, so it can proceed
393 : * even in abort state, but we must not update the super block if
394 : * checkpointing may have failed. Otherwise, we would lose some metadata
395 : * buffers which should be written-back to the filesystem.
396 : */
397 :
398 0 : int jbd2_cleanup_journal_tail(journal_t *journal)
399 : {
400 0 : tid_t first_tid;
401 0 : unsigned long blocknr;
402 :
403 0 : if (is_journal_aborted(journal))
404 : return -EIO;
405 :
406 0 : if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr))
407 : return 1;
408 0 : J_ASSERT(blocknr != 0);
409 :
410 : /*
411 : * We need to make sure that any blocks that were recently written out
412 : * --- perhaps by jbd2_log_do_checkpoint() --- are flushed out before
413 : * we drop the transactions from the journal. It's unlikely this will
414 : * be necessary, especially with an appropriately sized journal, but we
415 : * need this to guarantee correctness. Fortunately
416 : * jbd2_cleanup_journal_tail() doesn't get called all that often.
417 : */
418 0 : if (journal->j_flags & JBD2_BARRIER)
419 0 : blkdev_issue_flush(journal->j_fs_dev);
420 :
421 0 : return __jbd2_update_log_tail(journal, first_tid, blocknr);
422 : }
423 :
424 :
425 : /* Checkpoint list management */
426 :
427 : /*
428 : * journal_clean_one_cp_list
429 : *
430 : * Find all the written-back checkpoint buffers in the given list and
431 : * release them. If 'destroy' is set, clean all buffers unconditionally.
432 : *
433 : * Called with j_list_lock held.
434 : * Returns 1 if we freed the transaction, 0 otherwise.
435 : */
436 155 : static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy)
437 : {
438 155 : struct journal_head *last_jh;
439 155 : struct journal_head *next_jh = jh;
440 155 : int ret;
441 :
442 155 : if (!jh)
443 : return 0;
444 :
445 98 : last_jh = jh->b_cpprev;
446 713 : do {
447 713 : jh = next_jh;
448 713 : next_jh = jh->b_cpnext;
449 713 : if (!destroy)
450 713 : ret = __try_to_free_cp_buf(jh);
451 : else
452 0 : ret = __jbd2_journal_remove_checkpoint(jh) + 1;
453 713 : if (!ret)
454 : return 0;
455 656 : if (ret == 2)
456 : return 1;
457 : /*
458 : * This function only frees up some memory
459 : * if possible so we dont have an obligation
460 : * to finish processing. Bail out if preemption
461 : * requested:
462 : */
463 615 : if (need_resched())
464 : return 0;
465 615 : } while (jh != last_jh);
466 :
467 : return 0;
468 : }
469 :
470 : /*
471 : * journal_clean_checkpoint_list
472 : *
473 : * Find all the written-back checkpoint buffers in the journal and release them.
474 : * If 'destroy' is set, release all buffers unconditionally.
475 : *
476 : * Called with j_list_lock held.
477 : */
478 58 : void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy)
479 : {
480 58 : transaction_t *transaction, *last_transaction, *next_transaction;
481 58 : int ret;
482 :
483 58 : transaction = journal->j_checkpoint_transactions;
484 58 : if (!transaction)
485 : return;
486 :
487 57 : last_transaction = transaction->t_cpprev;
488 57 : next_transaction = transaction;
489 98 : do {
490 98 : transaction = next_transaction;
491 98 : next_transaction = transaction->t_cpnext;
492 98 : ret = journal_clean_one_cp_list(transaction->t_checkpoint_list,
493 : destroy);
494 : /*
495 : * This function only frees up some memory if possible so we
496 : * dont have an obligation to finish processing. Bail out if
497 : * preemption requested:
498 : */
499 98 : if (need_resched())
500 : return;
501 98 : if (ret)
502 41 : continue;
503 : /*
504 : * It is essential that we are as careful as in the case of
505 : * t_checkpoint_list with removing the buffer from the list as
506 : * we can possibly see not yet submitted buffers on io_list
507 : */
508 57 : ret = journal_clean_one_cp_list(transaction->
509 : t_checkpoint_io_list, destroy);
510 57 : if (need_resched())
511 : return;
512 : /*
513 : * Stop scanning if we couldn't free the transaction. This
514 : * avoids pointless scanning of transactions which still
515 : * weren't checkpointed.
516 : */
517 57 : if (!ret)
518 : return;
519 41 : } while (transaction != last_transaction);
520 : }
521 :
522 : /*
523 : * Remove buffers from all checkpoint lists as journal is aborted and we just
524 : * need to free memory
525 : */
526 0 : void jbd2_journal_destroy_checkpoint(journal_t *journal)
527 : {
528 : /*
529 : * We loop because __jbd2_journal_clean_checkpoint_list() may abort
530 : * early due to a need of rescheduling.
531 : */
532 0 : while (1) {
533 0 : spin_lock(&journal->j_list_lock);
534 0 : if (!journal->j_checkpoint_transactions) {
535 0 : spin_unlock(&journal->j_list_lock);
536 0 : break;
537 : }
538 0 : __jbd2_journal_clean_checkpoint_list(journal, true);
539 0 : spin_unlock(&journal->j_list_lock);
540 0 : cond_resched();
541 : }
542 0 : }
543 :
544 : /*
545 : * journal_remove_checkpoint: called after a buffer has been committed
546 : * to disk (either by being write-back flushed to disk, or being
547 : * committed to the log).
548 : *
549 : * We cannot safely clean a transaction out of the log until all of the
550 : * buffer updates committed in that transaction have safely been stored
551 : * elsewhere on disk. To achieve this, all of the buffers in a
552 : * transaction need to be maintained on the transaction's checkpoint
553 : * lists until they have been rewritten, at which point this function is
554 : * called to remove the buffer from the existing transaction's
555 : * checkpoint lists.
556 : *
557 : * The function returns 1 if it frees the transaction, 0 otherwise.
558 : * The function can free jh and bh.
559 : *
560 : * This function is called with j_list_lock held.
561 : */
562 1589 : int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
563 : {
564 1589 : struct transaction_chp_stats_s *stats;
565 1589 : transaction_t *transaction;
566 1589 : journal_t *journal;
567 1589 : int ret = 0;
568 :
569 1589 : JBUFFER_TRACE(jh, "entry");
570 :
571 1589 : if ((transaction = jh->b_cp_transaction) == NULL) {
572 0 : JBUFFER_TRACE(jh, "not on transaction");
573 0 : goto out;
574 : }
575 1589 : journal = transaction->t_journal;
576 :
577 1589 : JBUFFER_TRACE(jh, "removing from transaction");
578 1589 : __buffer_unlink(jh);
579 1589 : jh->b_cp_transaction = NULL;
580 1589 : jbd2_journal_put_journal_head(jh);
581 :
582 1589 : if (transaction->t_checkpoint_list != NULL ||
583 51 : transaction->t_checkpoint_io_list != NULL)
584 1538 : goto out;
585 :
586 : /*
587 : * There is one special case to worry about: if we have just pulled the
588 : * buffer off a running or committing transaction's checkpoing list,
589 : * then even if the checkpoint list is empty, the transaction obviously
590 : * cannot be dropped!
591 : *
592 : * The locking here around t_state is a bit sleazy.
593 : * See the comment at the end of jbd2_journal_commit_transaction().
594 : */
595 51 : if (transaction->t_state != T_FINISHED)
596 0 : goto out;
597 :
598 : /* OK, that was the last buffer for the transaction: we can now
599 : safely remove this transaction from the log */
600 51 : stats = &transaction->t_chp_stats;
601 51 : if (stats->cs_chp_time)
602 0 : stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time,
603 : jiffies);
604 51 : trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev,
605 51 : transaction->t_tid, stats);
606 :
607 51 : __jbd2_journal_drop_transaction(journal, transaction);
608 51 : jbd2_journal_free_transaction(transaction);
609 51 : ret = 1;
610 1589 : out:
611 1589 : return ret;
612 : }
613 :
614 : /*
615 : * journal_insert_checkpoint: put a committed buffer onto a checkpoint
616 : * list so that we know when it is safe to clean the transaction out of
617 : * the log.
618 : *
619 : * Called with the journal locked.
620 : * Called with j_list_lock held.
621 : */
622 1844 : void __jbd2_journal_insert_checkpoint(struct journal_head *jh,
623 : transaction_t *transaction)
624 : {
625 1844 : JBUFFER_TRACE(jh, "entry");
626 1844 : J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh)));
627 1844 : J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
628 :
629 : /* Get reference for checkpointing transaction */
630 1844 : jbd2_journal_grab_journal_head(jh2bh(jh));
631 1844 : jh->b_cp_transaction = transaction;
632 :
633 1844 : if (!transaction->t_checkpoint_list) {
634 58 : jh->b_cpnext = jh->b_cpprev = jh;
635 : } else {
636 1786 : jh->b_cpnext = transaction->t_checkpoint_list;
637 1786 : jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev;
638 1786 : jh->b_cpprev->b_cpnext = jh;
639 1786 : jh->b_cpnext->b_cpprev = jh;
640 : }
641 1844 : transaction->t_checkpoint_list = jh;
642 1844 : }
643 :
644 : /*
645 : * We've finished with this transaction structure: adios...
646 : *
647 : * The transaction must have no links except for the checkpoint by this
648 : * point.
649 : *
650 : * Called with the journal locked.
651 : * Called with j_list_lock held.
652 : */
653 :
654 51 : void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction)
655 : {
656 51 : assert_spin_locked(&journal->j_list_lock);
657 51 : if (transaction->t_cpnext) {
658 51 : transaction->t_cpnext->t_cpprev = transaction->t_cpprev;
659 51 : transaction->t_cpprev->t_cpnext = transaction->t_cpnext;
660 51 : if (journal->j_checkpoint_transactions == transaction)
661 41 : journal->j_checkpoint_transactions =
662 : transaction->t_cpnext;
663 51 : if (journal->j_checkpoint_transactions == transaction)
664 0 : journal->j_checkpoint_transactions = NULL;
665 : }
666 :
667 51 : J_ASSERT(transaction->t_state == T_FINISHED);
668 51 : J_ASSERT(transaction->t_buffers == NULL);
669 51 : J_ASSERT(transaction->t_forget == NULL);
670 51 : J_ASSERT(transaction->t_shadow_list == NULL);
671 51 : J_ASSERT(transaction->t_checkpoint_list == NULL);
672 51 : J_ASSERT(transaction->t_checkpoint_io_list == NULL);
673 51 : J_ASSERT(atomic_read(&transaction->t_updates) == 0);
674 51 : J_ASSERT(journal->j_committing_transaction != transaction);
675 51 : J_ASSERT(journal->j_running_transaction != transaction);
676 :
677 51 : trace_jbd2_drop_transaction(journal, transaction);
678 :
679 51 : jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid);
680 51 : }
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