blob: 4227dc4f7437d51c8171709a7e09eef46a09f8cd [file] [log] [blame]
Dave Kleikamp470decc2006-10-11 01:20:57 -07001/*
Uwe Kleine-König58862692007-05-09 07:51:49 +02002 * linux/fs/jbd2/checkpoint.c
Dave Kleikamp470decc2006-10-11 01:20:57 -07003 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
5 *
6 * Copyright 1999 Red Hat Software --- All Rights Reserved
7 *
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
11 *
12 * Checkpoint routines for the generic filesystem journaling code.
13 * Part of the ext2fs journaling system.
14 *
15 * Checkpointing is the process of ensuring that a section of the log is
16 * committed fully to disk, so that that portion of the log can be
17 * reused.
18 */
19
20#include <linux/time.h>
21#include <linux/fs.h>
Mingming Caof7f4bcc2006-10-11 01:20:59 -070022#include <linux/jbd2.h>
Dave Kleikamp470decc2006-10-11 01:20:57 -070023#include <linux/errno.h>
24#include <linux/slab.h>
Theodore Ts'occ3e1be2009-12-23 06:52:08 -050025#include <linux/blkdev.h>
Theodore Ts'o879c5e62009-06-17 11:47:48 -040026#include <trace/events/jbd2.h>
Dave Kleikamp470decc2006-10-11 01:20:57 -070027
28/*
29 * Unlink a buffer from a transaction checkpoint list.
30 *
31 * Called with j_list_lock held.
32 */
33static inline void __buffer_unlink_first(struct journal_head *jh)
34{
35 transaction_t *transaction = jh->b_cp_transaction;
36
37 jh->b_cpnext->b_cpprev = jh->b_cpprev;
38 jh->b_cpprev->b_cpnext = jh->b_cpnext;
39 if (transaction->t_checkpoint_list == jh) {
40 transaction->t_checkpoint_list = jh->b_cpnext;
41 if (transaction->t_checkpoint_list == jh)
42 transaction->t_checkpoint_list = NULL;
43 }
44}
45
46/*
47 * Unlink a buffer from a transaction checkpoint(io) list.
48 *
49 * Called with j_list_lock held.
50 */
51static inline void __buffer_unlink(struct journal_head *jh)
52{
53 transaction_t *transaction = jh->b_cp_transaction;
54
55 __buffer_unlink_first(jh);
56 if (transaction->t_checkpoint_io_list == jh) {
57 transaction->t_checkpoint_io_list = jh->b_cpnext;
58 if (transaction->t_checkpoint_io_list == jh)
59 transaction->t_checkpoint_io_list = NULL;
60 }
61}
62
63/*
64 * Move a buffer from the checkpoint list to the checkpoint io list
65 *
66 * Called with j_list_lock held
67 */
68static inline void __buffer_relink_io(struct journal_head *jh)
69{
70 transaction_t *transaction = jh->b_cp_transaction;
71
72 __buffer_unlink_first(jh);
73
74 if (!transaction->t_checkpoint_io_list) {
75 jh->b_cpnext = jh->b_cpprev = jh;
76 } else {
77 jh->b_cpnext = transaction->t_checkpoint_io_list;
78 jh->b_cpprev = transaction->t_checkpoint_io_list->b_cpprev;
79 jh->b_cpprev->b_cpnext = jh;
80 jh->b_cpnext->b_cpprev = jh;
81 }
82 transaction->t_checkpoint_io_list = jh;
83}
84
85/*
86 * Try to release a checkpointed buffer from its transaction.
87 * Returns 1 if we released it and 2 if we also released the
88 * whole transaction.
89 *
90 * Requires j_list_lock
Dave Kleikamp470decc2006-10-11 01:20:57 -070091 */
92static int __try_to_free_cp_buf(struct journal_head *jh)
93{
94 int ret = 0;
95 struct buffer_head *bh = jh2bh(jh);
96
Jan Kara932bb302012-03-13 22:45:25 -040097 if (jh->b_transaction == NULL && !buffer_locked(bh) &&
Hidehiro Kawai44519fa2008-10-10 20:29:13 -040098 !buffer_dirty(bh) && !buffer_write_io_error(bh)) {
Dave Kleikamp470decc2006-10-11 01:20:57 -070099 JBUFFER_TRACE(jh, "remove from checkpoint list");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700100 ret = __jbd2_journal_remove_checkpoint(jh) + 1;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700101 }
102 return ret;
103}
104
105/*
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700106 * __jbd2_log_wait_for_space: wait until there is space in the journal.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700107 *
108 * Called under j-state_lock *only*. It will be unlocked if we have to wait
109 * for a checkpoint to free up some space in the log.
110 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700111void __jbd2_log_wait_for_space(journal_t *journal)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700112{
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500113 int nblocks, space_left;
Theodore Ts'oa931da62010-08-03 21:35:12 -0400114 /* assert_spin_locked(&journal->j_state_lock); */
Dave Kleikamp470decc2006-10-11 01:20:57 -0700115
Jan Kara76c39902013-06-04 12:12:57 -0400116 nblocks = jbd2_space_needed(journal);
117 while (jbd2_log_space_left(journal) < nblocks) {
Theodore Ts'oa931da62010-08-03 21:35:12 -0400118 write_unlock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700119 mutex_lock(&journal->j_checkpoint_mutex);
120
121 /*
122 * Test again, another process may have checkpointed while we
Duane Griffin23f8b792008-10-08 23:28:31 -0400123 * were waiting for the checkpoint lock. If there are no
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500124 * transactions ready to be checkpointed, try to recover
125 * journal space by calling cleanup_journal_tail(), and if
126 * that doesn't work, by waiting for the currently committing
127 * transaction to complete. If there is absolutely no way
128 * to make progress, this is either a BUG or corrupted
129 * filesystem, so abort the journal and leave a stack
130 * trace for forensic evidence.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700131 */
Theodore Ts'oa931da62010-08-03 21:35:12 -0400132 write_lock(&journal->j_state_lock);
Dmitry Monakhov12457992014-09-16 14:50:50 -0400133 if (journal->j_flags & JBD2_ABORT) {
134 mutex_unlock(&journal->j_checkpoint_mutex);
135 return;
136 }
Duane Griffin23f8b792008-10-08 23:28:31 -0400137 spin_lock(&journal->j_list_lock);
Jan Kara76c39902013-06-04 12:12:57 -0400138 nblocks = jbd2_space_needed(journal);
139 space_left = jbd2_log_space_left(journal);
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500140 if (space_left < nblocks) {
Duane Griffin23f8b792008-10-08 23:28:31 -0400141 int chkpt = journal->j_checkpoint_transactions != NULL;
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500142 tid_t tid = 0;
Duane Griffin23f8b792008-10-08 23:28:31 -0400143
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500144 if (journal->j_committing_transaction)
145 tid = journal->j_committing_transaction->t_tid;
Duane Griffin23f8b792008-10-08 23:28:31 -0400146 spin_unlock(&journal->j_list_lock);
Theodore Ts'oa931da62010-08-03 21:35:12 -0400147 write_unlock(&journal->j_state_lock);
Duane Griffin23f8b792008-10-08 23:28:31 -0400148 if (chkpt) {
149 jbd2_log_do_checkpoint(journal);
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500150 } else if (jbd2_cleanup_journal_tail(journal) == 0) {
151 /* We were able to recover space; yay! */
152 ;
153 } else if (tid) {
Paul Gortmaker0ef54182013-06-12 22:47:35 -0400154 /*
155 * jbd2_journal_commit_transaction() may want
156 * to take the checkpoint_mutex if JBD2_FLUSHED
157 * is set. So we need to temporarily drop it.
158 */
159 mutex_unlock(&journal->j_checkpoint_mutex);
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500160 jbd2_log_wait_commit(journal, tid);
Paul Gortmaker0ef54182013-06-12 22:47:35 -0400161 write_lock(&journal->j_state_lock);
162 continue;
Duane Griffin23f8b792008-10-08 23:28:31 -0400163 } else {
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500164 printk(KERN_ERR "%s: needed %d blocks and "
165 "only had %d space available\n",
166 __func__, nblocks, space_left);
167 printk(KERN_ERR "%s: no way to get more "
168 "journal space in %s\n", __func__,
169 journal->j_devname);
170 WARN_ON(1);
Duane Griffin23f8b792008-10-08 23:28:31 -0400171 jbd2_journal_abort(journal, 0);
172 }
Theodore Ts'oa931da62010-08-03 21:35:12 -0400173 write_lock(&journal->j_state_lock);
Duane Griffin23f8b792008-10-08 23:28:31 -0400174 } else {
175 spin_unlock(&journal->j_list_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700176 }
177 mutex_unlock(&journal->j_checkpoint_mutex);
178 }
179}
180
Dave Kleikamp470decc2006-10-11 01:20:57 -0700181static void
Theodore Ts'o1a0d3782008-11-05 00:09:22 -0500182__flush_batch(journal_t *journal, int *batch_count)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700183{
184 int i;
Tao Mad3ad8432011-06-27 12:36:29 -0400185 struct blk_plug plug;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700186
Tao Mad3ad8432011-06-27 12:36:29 -0400187 blk_start_plug(&plug);
Christoph Hellwig9cb569d2010-08-11 17:06:24 +0200188 for (i = 0; i < *batch_count; i++)
Tao Mad3ad8432011-06-27 12:36:29 -0400189 write_dirty_buffer(journal->j_chkpt_bhs[i], WRITE_SYNC);
190 blk_finish_plug(&plug);
Christoph Hellwig9cb569d2010-08-11 17:06:24 +0200191
Dave Kleikamp470decc2006-10-11 01:20:57 -0700192 for (i = 0; i < *batch_count; i++) {
Theodore Ts'o1a0d3782008-11-05 00:09:22 -0500193 struct buffer_head *bh = journal->j_chkpt_bhs[i];
Dave Kleikamp470decc2006-10-11 01:20:57 -0700194 BUFFER_TRACE(bh, "brelse");
195 __brelse(bh);
196 }
197 *batch_count = 0;
198}
199
200/*
Dave Kleikamp470decc2006-10-11 01:20:57 -0700201 * Perform an actual checkpoint. We take the first transaction on the
202 * list of transactions to be checkpointed and send all its buffers
203 * to disk. We submit larger chunks of data at once.
204 *
205 * The journal should be locked before calling this function.
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400206 * Called with j_checkpoint_mutex held.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700207 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700208int jbd2_log_do_checkpoint(journal_t *journal)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700209{
Theodore Ts'obe1158c2014-09-01 21:19:01 -0400210 struct journal_head *jh;
211 struct buffer_head *bh;
212 transaction_t *transaction;
213 tid_t this_tid;
Theodore Ts'odc6e8d62014-09-04 18:09:22 -0400214 int result, batch_count = 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700215
216 jbd_debug(1, "Start checkpoint\n");
217
218 /*
219 * First thing: if there are any transactions in the log which
220 * don't need checkpointing, just eliminate them from the
221 * journal straight away.
222 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700223 result = jbd2_cleanup_journal_tail(journal);
Theodore Ts'o879c5e62009-06-17 11:47:48 -0400224 trace_jbd2_checkpoint(journal, result);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700225 jbd_debug(1, "cleanup_journal_tail returned %d\n", result);
226 if (result <= 0)
227 return result;
228
229 /*
230 * OK, we need to start writing disk blocks. Take one transaction
231 * and write it.
232 */
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400233 result = 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700234 spin_lock(&journal->j_list_lock);
235 if (!journal->j_checkpoint_transactions)
236 goto out;
237 transaction = journal->j_checkpoint_transactions;
Johann Lombardi8e85fb32008-01-28 23:58:27 -0500238 if (transaction->t_chp_stats.cs_chp_time == 0)
239 transaction->t_chp_stats.cs_chp_time = jiffies;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700240 this_tid = transaction->t_tid;
241restart:
242 /*
243 * If someone cleaned up this transaction while we slept, we're
244 * done (maybe it's a new transaction, but it fell at the same
245 * address).
246 */
Theodore Ts'obe1158c2014-09-01 21:19:01 -0400247 if (journal->j_checkpoint_transactions != transaction ||
248 transaction->t_tid != this_tid)
249 goto out;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700250
Theodore Ts'obe1158c2014-09-01 21:19:01 -0400251 /* checkpoint all of the transaction's buffers */
252 while (transaction->t_checkpoint_list) {
253 jh = transaction->t_checkpoint_list;
254 bh = jh2bh(jh);
255
256 if (buffer_locked(bh)) {
257 spin_unlock(&journal->j_list_lock);
258 get_bh(bh);
259 wait_on_buffer(bh);
260 /* the journal_head may have gone by now */
261 BUFFER_TRACE(bh, "brelse");
262 __brelse(bh);
263 goto retry;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700264 }
Theodore Ts'obe1158c2014-09-01 21:19:01 -0400265 if (jh->b_transaction != NULL) {
266 transaction_t *t = jh->b_transaction;
267 tid_t tid = t->t_tid;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700268
Theodore Ts'obe1158c2014-09-01 21:19:01 -0400269 transaction->t_chp_stats.cs_forced_to_close++;
270 spin_unlock(&journal->j_list_lock);
271 if (unlikely(journal->j_flags & JBD2_UNMOUNT))
272 /*
273 * The journal thread is dead; so
274 * starting and waiting for a commit
275 * to finish will cause us to wait for
276 * a _very_ long time.
277 */
278 printk(KERN_ERR
279 "JBD2: %s: Waiting for Godot: block %llu\n",
280 journal->j_devname, (unsigned long long) bh->b_blocknr);
281
282 jbd2_log_start_commit(journal, tid);
283 jbd2_log_wait_commit(journal, tid);
284 goto retry;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700285 }
Theodore Ts'obe1158c2014-09-01 21:19:01 -0400286 if (!buffer_dirty(bh)) {
287 if (unlikely(buffer_write_io_error(bh)) && !result)
288 result = -EIO;
Theodore Ts'obe1158c2014-09-01 21:19:01 -0400289 BUFFER_TRACE(bh, "remove from checkpoint");
Jan Kara0e5ecf0a2014-09-04 18:09:29 -0400290 if (__jbd2_journal_remove_checkpoint(jh))
291 /* The transaction was released; we're done */
292 goto out;
293 continue;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700294 }
295 /*
Theodore Ts'obe1158c2014-09-01 21:19:01 -0400296 * Important: we are about to write the buffer, and
297 * possibly block, while still holding the journal
298 * lock. We cannot afford to let the transaction
299 * logic start messing around with this buffer before
300 * we write it to disk, as that would break
301 * recoverability.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700302 */
Theodore Ts'obe1158c2014-09-01 21:19:01 -0400303 BUFFER_TRACE(bh, "queue");
304 get_bh(bh);
305 J_ASSERT_BH(bh, !buffer_jwrite(bh));
306 journal->j_chkpt_bhs[batch_count++] = bh;
307 __buffer_relink_io(jh);
308 transaction->t_chp_stats.cs_written++;
309 if ((batch_count == JBD2_NR_BATCH) ||
310 need_resched() ||
311 spin_needbreak(&journal->j_list_lock))
312 goto unlock_and_flush;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700313 }
Theodore Ts'obe1158c2014-09-01 21:19:01 -0400314
315 if (batch_count) {
316 unlock_and_flush:
317 spin_unlock(&journal->j_list_lock);
318 retry:
319 if (batch_count)
320 __flush_batch(journal, &batch_count);
321 spin_lock(&journal->j_list_lock);
322 goto restart;
323 }
324
325 /*
326 * Now we issued all of the transaction's buffers, let's deal
327 * with the buffers that are out for I/O.
328 */
Theodore Ts'o88fe1ac2014-09-01 21:26:09 -0400329restart2:
330 /* Did somebody clean up the transaction in the meanwhile? */
331 if (journal->j_checkpoint_transactions != transaction ||
332 transaction->t_tid != this_tid)
333 goto out;
334
Theodore Ts'odc6e8d62014-09-04 18:09:22 -0400335 while (transaction->t_checkpoint_io_list) {
Theodore Ts'o88fe1ac2014-09-01 21:26:09 -0400336 jh = transaction->t_checkpoint_io_list;
337 bh = jh2bh(jh);
Theodore Ts'o88fe1ac2014-09-01 21:26:09 -0400338 if (buffer_locked(bh)) {
339 spin_unlock(&journal->j_list_lock);
Theodore Ts'odc6e8d62014-09-04 18:09:22 -0400340 get_bh(bh);
Theodore Ts'o88fe1ac2014-09-01 21:26:09 -0400341 wait_on_buffer(bh);
342 /* the journal_head may have gone by now */
343 BUFFER_TRACE(bh, "brelse");
344 __brelse(bh);
345 spin_lock(&journal->j_list_lock);
346 goto restart2;
347 }
348 if (unlikely(buffer_write_io_error(bh)) && !result)
349 result = -EIO;
350
351 /*
352 * Now in whatever state the buffer currently is, we
353 * know that it has been written out and so we can
354 * drop it from the list
355 */
Theodore Ts'odc6e8d62014-09-04 18:09:22 -0400356 if (__jbd2_journal_remove_checkpoint(jh))
357 break;
Theodore Ts'o88fe1ac2014-09-01 21:26:09 -0400358 }
Dave Kleikamp470decc2006-10-11 01:20:57 -0700359out:
360 spin_unlock(&journal->j_list_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700361 if (result < 0)
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400362 jbd2_journal_abort(journal, result);
363 else
364 result = jbd2_cleanup_journal_tail(journal);
365
366 return (result < 0) ? result : 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700367}
368
369/*
370 * Check the list of checkpoint transactions for the journal to see if
371 * we have already got rid of any since the last update of the log tail
372 * in the journal superblock. If so, we can instantly roll the
373 * superblock forward to remove those transactions from the log.
374 *
375 * Return <0 on error, 0 on success, 1 if there was nothing to clean up.
376 *
377 * Called with the journal lock held.
378 *
379 * This is the only part of the journaling code which really needs to be
380 * aware of transaction aborts. Checkpointing involves writing to the
381 * main filesystem area rather than to the journal, so it can proceed
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400382 * even in abort state, but we must not update the super block if
383 * checkpointing may have failed. Otherwise, we would lose some metadata
384 * buffers which should be written-back to the filesystem.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700385 */
386
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700387int jbd2_cleanup_journal_tail(journal_t *journal)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700388{
Dave Kleikamp470decc2006-10-11 01:20:57 -0700389 tid_t first_tid;
Jan Kara79feb522012-03-13 22:22:54 -0400390 unsigned long blocknr;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700391
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400392 if (is_journal_aborted(journal))
Joseph Qi6f6a6fd2015-06-15 14:36:01 -0400393 return -EIO;
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400394
Jan Kara79feb522012-03-13 22:22:54 -0400395 if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr))
396 return 1;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700397 J_ASSERT(blocknr != 0);
398
Theodore Ts'occ3e1be2009-12-23 06:52:08 -0500399 /*
Jan Kara79feb522012-03-13 22:22:54 -0400400 * We need to make sure that any blocks that were recently written out
401 * --- perhaps by jbd2_log_do_checkpoint() --- are flushed out before
402 * we drop the transactions from the journal. It's unlikely this will
403 * be necessary, especially with an appropriately sized journal, but we
404 * need this to guarantee correctness. Fortunately
405 * jbd2_cleanup_journal_tail() doesn't get called all that often.
Theodore Ts'occ3e1be2009-12-23 06:52:08 -0500406 */
Jan Kara79feb522012-03-13 22:22:54 -0400407 if (journal->j_flags & JBD2_BARRIER)
Dmitry Monakhovb4f1afc2015-06-15 00:18:02 -0400408 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
Jan Kara79feb522012-03-13 22:22:54 -0400409
Joseph Qi6f6a6fd2015-06-15 14:36:01 -0400410 return __jbd2_update_log_tail(journal, first_tid, blocknr);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700411}
412
413
414/* Checkpoint list management */
415
416/*
417 * journal_clean_one_cp_list
418 *
Jan Karade1b7942011-06-13 15:38:22 -0400419 * Find all the written-back checkpoint buffers in the given list and
420 * release them.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700421 *
Dave Kleikamp470decc2006-10-11 01:20:57 -0700422 * Called with j_list_lock held.
Jan Kara50849db2014-09-18 00:58:12 -0400423 * Returns 1 if we freed the transaction, 0 otherwise.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700424 */
Jan Kara50849db2014-09-18 00:58:12 -0400425static int journal_clean_one_cp_list(struct journal_head *jh)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700426{
427 struct journal_head *last_jh;
428 struct journal_head *next_jh = jh;
Jan Kara50849db2014-09-18 00:58:12 -0400429 int ret;
430 int freed = 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700431
Dave Kleikamp470decc2006-10-11 01:20:57 -0700432 if (!jh)
433 return 0;
434
435 last_jh = jh->b_cpprev;
436 do {
437 jh = next_jh;
438 next_jh = jh->b_cpnext;
Jan Kara932bb302012-03-13 22:45:25 -0400439 ret = __try_to_free_cp_buf(jh);
Jan Karacc97f1a2014-09-18 00:42:16 -0400440 if (!ret)
441 return freed;
Jan Kara50849db2014-09-18 00:58:12 -0400442 if (ret == 2)
443 return 1;
444 freed = 1;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700445 /*
446 * This function only frees up some memory
447 * if possible so we dont have an obligation
448 * to finish processing. Bail out if preemption
449 * requested:
450 */
451 if (need_resched())
452 return freed;
453 } while (jh != last_jh);
454
455 return freed;
456}
457
458/*
459 * journal_clean_checkpoint_list
460 *
461 * Find all the written-back checkpoint buffers in the journal and release them.
462 *
Dave Kleikamp470decc2006-10-11 01:20:57 -0700463 * Called with j_list_lock held.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700464 */
Jan Kara50849db2014-09-18 00:58:12 -0400465void __jbd2_journal_clean_checkpoint_list(journal_t *journal)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700466{
467 transaction_t *transaction, *last_transaction, *next_transaction;
Jan Karacc97f1a2014-09-18 00:42:16 -0400468 int ret;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700469
470 transaction = journal->j_checkpoint_transactions;
471 if (!transaction)
Jan Kara50849db2014-09-18 00:58:12 -0400472 return;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700473
474 last_transaction = transaction->t_cpprev;
475 next_transaction = transaction;
476 do {
477 transaction = next_transaction;
478 next_transaction = transaction->t_cpnext;
Jan Kara50849db2014-09-18 00:58:12 -0400479 ret = journal_clean_one_cp_list(transaction->t_checkpoint_list);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700480 /*
481 * This function only frees up some memory if possible so we
482 * dont have an obligation to finish processing. Bail out if
483 * preemption requested:
484 */
Jan Kara50849db2014-09-18 00:58:12 -0400485 if (need_resched())
486 return;
487 if (ret)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700488 continue;
489 /*
490 * It is essential that we are as careful as in the case of
491 * t_checkpoint_list with removing the buffer from the list as
492 * we can possibly see not yet submitted buffers on io_list
493 */
Jan Kara50849db2014-09-18 00:58:12 -0400494 ret = journal_clean_one_cp_list(transaction->
495 t_checkpoint_io_list);
496 if (need_resched())
497 return;
498 /*
499 * Stop scanning if we couldn't free the transaction. This
500 * avoids pointless scanning of transactions which still
501 * weren't checkpointed.
502 */
503 if (!ret)
504 return;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700505 } while (transaction != last_transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700506}
507
508/*
509 * journal_remove_checkpoint: called after a buffer has been committed
510 * to disk (either by being write-back flushed to disk, or being
511 * committed to the log).
512 *
513 * We cannot safely clean a transaction out of the log until all of the
514 * buffer updates committed in that transaction have safely been stored
515 * elsewhere on disk. To achieve this, all of the buffers in a
516 * transaction need to be maintained on the transaction's checkpoint
517 * lists until they have been rewritten, at which point this function is
518 * called to remove the buffer from the existing transaction's
519 * checkpoint lists.
520 *
521 * The function returns 1 if it frees the transaction, 0 otherwise.
Jan Karade1b7942011-06-13 15:38:22 -0400522 * The function can free jh and bh.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700523 *
Dave Kleikamp470decc2006-10-11 01:20:57 -0700524 * This function is called with j_list_lock held.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700525 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700526int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700527{
Theodore Ts'obf699322009-09-30 00:32:06 -0400528 struct transaction_chp_stats_s *stats;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700529 transaction_t *transaction;
530 journal_t *journal;
531 int ret = 0;
532
533 JBUFFER_TRACE(jh, "entry");
534
535 if ((transaction = jh->b_cp_transaction) == NULL) {
536 JBUFFER_TRACE(jh, "not on transaction");
537 goto out;
538 }
539 journal = transaction->t_journal;
540
Jan Karade1b7942011-06-13 15:38:22 -0400541 JBUFFER_TRACE(jh, "removing from transaction");
Dave Kleikamp470decc2006-10-11 01:20:57 -0700542 __buffer_unlink(jh);
543 jh->b_cp_transaction = NULL;
Jan Karade1b7942011-06-13 15:38:22 -0400544 jbd2_journal_put_journal_head(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700545
546 if (transaction->t_checkpoint_list != NULL ||
547 transaction->t_checkpoint_io_list != NULL)
548 goto out;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700549
550 /*
551 * There is one special case to worry about: if we have just pulled the
Jan Karaf5a7a6b2008-01-28 23:58:27 -0500552 * buffer off a running or committing transaction's checkpoing list,
553 * then even if the checkpoint list is empty, the transaction obviously
554 * cannot be dropped!
Dave Kleikamp470decc2006-10-11 01:20:57 -0700555 *
Jan Karaf5a7a6b2008-01-28 23:58:27 -0500556 * The locking here around t_state is a bit sleazy.
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700557 * See the comment at the end of jbd2_journal_commit_transaction().
Dave Kleikamp470decc2006-10-11 01:20:57 -0700558 */
Jan Karade1b7942011-06-13 15:38:22 -0400559 if (transaction->t_state != T_FINISHED)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700560 goto out;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700561
562 /* OK, that was the last buffer for the transaction: we can now
563 safely remove this transaction from the log */
Theodore Ts'obf699322009-09-30 00:32:06 -0400564 stats = &transaction->t_chp_stats;
565 if (stats->cs_chp_time)
566 stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time,
567 jiffies);
568 trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev,
569 transaction->t_tid, stats);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700570
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700571 __jbd2_journal_drop_transaction(journal, transaction);
Yongqiang Yang0c2022e2012-02-20 17:53:02 -0500572 jbd2_journal_free_transaction(transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700573 ret = 1;
574out:
Dave Kleikamp470decc2006-10-11 01:20:57 -0700575 return ret;
576}
577
578/*
579 * journal_insert_checkpoint: put a committed buffer onto a checkpoint
580 * list so that we know when it is safe to clean the transaction out of
581 * the log.
582 *
583 * Called with the journal locked.
584 * Called with j_list_lock held.
585 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700586void __jbd2_journal_insert_checkpoint(struct journal_head *jh,
Dave Kleikamp470decc2006-10-11 01:20:57 -0700587 transaction_t *transaction)
588{
589 JBUFFER_TRACE(jh, "entry");
590 J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh)));
591 J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
592
Jan Karade1b7942011-06-13 15:38:22 -0400593 /* Get reference for checkpointing transaction */
594 jbd2_journal_grab_journal_head(jh2bh(jh));
Dave Kleikamp470decc2006-10-11 01:20:57 -0700595 jh->b_cp_transaction = transaction;
596
597 if (!transaction->t_checkpoint_list) {
598 jh->b_cpnext = jh->b_cpprev = jh;
599 } else {
600 jh->b_cpnext = transaction->t_checkpoint_list;
601 jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev;
602 jh->b_cpprev->b_cpnext = jh;
603 jh->b_cpnext->b_cpprev = jh;
604 }
605 transaction->t_checkpoint_list = jh;
606}
607
608/*
609 * We've finished with this transaction structure: adios...
610 *
611 * The transaction must have no links except for the checkpoint by this
612 * point.
613 *
614 * Called with the journal locked.
615 * Called with j_list_lock held.
616 */
617
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700618void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700619{
620 assert_spin_locked(&journal->j_list_lock);
621 if (transaction->t_cpnext) {
622 transaction->t_cpnext->t_cpprev = transaction->t_cpprev;
623 transaction->t_cpprev->t_cpnext = transaction->t_cpnext;
624 if (journal->j_checkpoint_transactions == transaction)
625 journal->j_checkpoint_transactions =
626 transaction->t_cpnext;
627 if (journal->j_checkpoint_transactions == transaction)
628 journal->j_checkpoint_transactions = NULL;
629 }
630
631 J_ASSERT(transaction->t_state == T_FINISHED);
632 J_ASSERT(transaction->t_buffers == NULL);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700633 J_ASSERT(transaction->t_forget == NULL);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700634 J_ASSERT(transaction->t_shadow_list == NULL);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700635 J_ASSERT(transaction->t_checkpoint_list == NULL);
636 J_ASSERT(transaction->t_checkpoint_io_list == NULL);
Theodore Ts'oa51dca92010-08-02 08:43:25 -0400637 J_ASSERT(atomic_read(&transaction->t_updates) == 0);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700638 J_ASSERT(journal->j_committing_transaction != transaction);
639 J_ASSERT(journal->j_running_transaction != transaction);
640
Seiji Aguchi2201c592012-02-20 17:53:01 -0500641 trace_jbd2_drop_transaction(journal, transaction);
642
Dave Kleikamp470decc2006-10-11 01:20:57 -0700643 jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700644}