blob: 6a79fd0a1a32cdd018fea9879a6026e4dcf9c8b6 [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 Caof7f4bccb2006-10-11 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
91 * Called under jbd_lock_bh_state(jh2bh(jh)), and drops it
92 */
93static int __try_to_free_cp_buf(struct journal_head *jh)
94{
95 int ret = 0;
96 struct buffer_head *bh = jh2bh(jh);
97
Hidehiro Kawai44519fa2008-10-10 20:29:13 -040098 if (jh->b_jlist == BJ_None && !buffer_locked(bh) &&
99 !buffer_dirty(bh) && !buffer_write_io_error(bh)) {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700100 JBUFFER_TRACE(jh, "remove from checkpoint list");
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700101 ret = __jbd2_journal_remove_checkpoint(jh) + 1;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700102 jbd_unlock_bh_state(bh);
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700103 jbd2_journal_remove_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700104 BUFFER_TRACE(bh, "release");
105 __brelse(bh);
106 } else {
107 jbd_unlock_bh_state(bh);
108 }
109 return ret;
110}
111
112/*
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700113 * __jbd2_log_wait_for_space: wait until there is space in the journal.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700114 *
115 * Called under j-state_lock *only*. It will be unlocked if we have to wait
116 * for a checkpoint to free up some space in the log.
117 */
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700118void __jbd2_log_wait_for_space(journal_t *journal)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700119{
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500120 int nblocks, space_left;
Theodore Ts'oa931da62010-08-03 21:35:12 -0400121 /* assert_spin_locked(&journal->j_state_lock); */
Dave Kleikamp470decc2006-10-11 01:20:57 -0700122
123 nblocks = jbd_space_needed(journal);
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700124 while (__jbd2_log_space_left(journal) < nblocks) {
125 if (journal->j_flags & JBD2_ABORT)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700126 return;
Theodore Ts'oa931da62010-08-03 21:35:12 -0400127 write_unlock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700128 mutex_lock(&journal->j_checkpoint_mutex);
129
130 /*
131 * Test again, another process may have checkpointed while we
Duane Griffin23f8b792008-10-08 23:28:31 -0400132 * were waiting for the checkpoint lock. If there are no
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500133 * transactions ready to be checkpointed, try to recover
134 * journal space by calling cleanup_journal_tail(), and if
135 * that doesn't work, by waiting for the currently committing
136 * transaction to complete. If there is absolutely no way
137 * to make progress, this is either a BUG or corrupted
138 * filesystem, so abort the journal and leave a stack
139 * trace for forensic evidence.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700140 */
Theodore Ts'oa931da62010-08-03 21:35:12 -0400141 write_lock(&journal->j_state_lock);
Duane Griffin23f8b792008-10-08 23:28:31 -0400142 spin_lock(&journal->j_list_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700143 nblocks = jbd_space_needed(journal);
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500144 space_left = __jbd2_log_space_left(journal);
145 if (space_left < nblocks) {
Duane Griffin23f8b792008-10-08 23:28:31 -0400146 int chkpt = journal->j_checkpoint_transactions != NULL;
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500147 tid_t tid = 0;
Duane Griffin23f8b792008-10-08 23:28:31 -0400148
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500149 if (journal->j_committing_transaction)
150 tid = journal->j_committing_transaction->t_tid;
Duane Griffin23f8b792008-10-08 23:28:31 -0400151 spin_unlock(&journal->j_list_lock);
Theodore Ts'oa931da62010-08-03 21:35:12 -0400152 write_unlock(&journal->j_state_lock);
Duane Griffin23f8b792008-10-08 23:28:31 -0400153 if (chkpt) {
154 jbd2_log_do_checkpoint(journal);
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500155 } else if (jbd2_cleanup_journal_tail(journal) == 0) {
156 /* We were able to recover space; yay! */
157 ;
158 } else if (tid) {
159 jbd2_log_wait_commit(journal, tid);
Duane Griffin23f8b792008-10-08 23:28:31 -0400160 } else {
Theodore Ts'o8c3f25d2008-11-06 22:38:07 -0500161 printk(KERN_ERR "%s: needed %d blocks and "
162 "only had %d space available\n",
163 __func__, nblocks, space_left);
164 printk(KERN_ERR "%s: no way to get more "
165 "journal space in %s\n", __func__,
166 journal->j_devname);
167 WARN_ON(1);
Duane Griffin23f8b792008-10-08 23:28:31 -0400168 jbd2_journal_abort(journal, 0);
169 }
Theodore Ts'oa931da62010-08-03 21:35:12 -0400170 write_lock(&journal->j_state_lock);
Duane Griffin23f8b792008-10-08 23:28:31 -0400171 } else {
172 spin_unlock(&journal->j_list_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700173 }
174 mutex_unlock(&journal->j_checkpoint_mutex);
175 }
176}
177
178/*
179 * We were unable to perform jbd_trylock_bh_state() inside j_list_lock.
180 * The caller must restart a list walk. Wait for someone else to run
181 * jbd_unlock_bh_state().
182 */
183static void jbd_sync_bh(journal_t *journal, struct buffer_head *bh)
184 __releases(journal->j_list_lock)
185{
186 get_bh(bh);
187 spin_unlock(&journal->j_list_lock);
188 jbd_lock_bh_state(bh);
189 jbd_unlock_bh_state(bh);
190 put_bh(bh);
191}
192
193/*
194 * Clean up transaction's list of buffers submitted for io.
195 * We wait for any pending IO to complete and remove any clean
196 * buffers. Note that we take the buffers in the opposite ordering
197 * from the one in which they were submitted for IO.
198 *
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400199 * Return 0 on success, and return <0 if some buffers have failed
200 * to be written out.
201 *
Dave Kleikamp470decc2006-10-11 01:20:57 -0700202 * Called with j_list_lock held.
203 */
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400204static int __wait_cp_io(journal_t *journal, transaction_t *transaction)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700205{
206 struct journal_head *jh;
207 struct buffer_head *bh;
208 tid_t this_tid;
209 int released = 0;
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400210 int ret = 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700211
212 this_tid = transaction->t_tid;
213restart:
214 /* Did somebody clean up the transaction in the meanwhile? */
215 if (journal->j_checkpoint_transactions != transaction ||
216 transaction->t_tid != this_tid)
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400217 return ret;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700218 while (!released && transaction->t_checkpoint_io_list) {
219 jh = transaction->t_checkpoint_io_list;
220 bh = jh2bh(jh);
221 if (!jbd_trylock_bh_state(bh)) {
222 jbd_sync_bh(journal, bh);
223 spin_lock(&journal->j_list_lock);
224 goto restart;
225 }
226 if (buffer_locked(bh)) {
227 atomic_inc(&bh->b_count);
228 spin_unlock(&journal->j_list_lock);
229 jbd_unlock_bh_state(bh);
230 wait_on_buffer(bh);
231 /* the journal_head may have gone by now */
232 BUFFER_TRACE(bh, "brelse");
233 __brelse(bh);
234 spin_lock(&journal->j_list_lock);
235 goto restart;
236 }
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400237 if (unlikely(buffer_write_io_error(bh)))
238 ret = -EIO;
239
Dave Kleikamp470decc2006-10-11 01:20:57 -0700240 /*
241 * Now in whatever state the buffer currently is, we know that
242 * it has been written out and so we can drop it from the list
243 */
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700244 released = __jbd2_journal_remove_checkpoint(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700245 jbd_unlock_bh_state(bh);
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700246 jbd2_journal_remove_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700247 __brelse(bh);
248 }
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400249
250 return ret;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700251}
252
Dave Kleikamp470decc2006-10-11 01:20:57 -0700253static void
Theodore Ts'o1a0d3782008-11-05 00:09:22 -0500254__flush_batch(journal_t *journal, int *batch_count)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700255{
256 int i;
257
Christoph Hellwig9cb569d2010-08-11 17:06:24 +0200258 for (i = 0; i < *batch_count; i++)
259 write_dirty_buffer(journal->j_chkpt_bhs[i], WRITE);
260
Dave Kleikamp470decc2006-10-11 01:20:57 -0700261 for (i = 0; i < *batch_count; i++) {
Theodore Ts'o1a0d3782008-11-05 00:09:22 -0500262 struct buffer_head *bh = journal->j_chkpt_bhs[i];
Dave Kleikamp470decc2006-10-11 01:20:57 -0700263 clear_buffer_jwrite(bh);
264 BUFFER_TRACE(bh, "brelse");
265 __brelse(bh);
266 }
267 *batch_count = 0;
268}
269
270/*
271 * Try to flush one buffer from the checkpoint list to disk.
272 *
273 * Return 1 if something happened which requires us to abort the current
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400274 * scan of the checkpoint list. Return <0 if the buffer has failed to
275 * be written out.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700276 *
277 * Called with j_list_lock held and drops it if 1 is returned
278 * Called under jbd_lock_bh_state(jh2bh(jh)), and drops it
279 */
280static int __process_buffer(journal_t *journal, struct journal_head *jh,
Theodore Ts'o1a0d3782008-11-05 00:09:22 -0500281 int *batch_count, transaction_t *transaction)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700282{
283 struct buffer_head *bh = jh2bh(jh);
284 int ret = 0;
285
286 if (buffer_locked(bh)) {
287 atomic_inc(&bh->b_count);
288 spin_unlock(&journal->j_list_lock);
289 jbd_unlock_bh_state(bh);
290 wait_on_buffer(bh);
291 /* the journal_head may have gone by now */
292 BUFFER_TRACE(bh, "brelse");
293 __brelse(bh);
294 ret = 1;
295 } else if (jh->b_transaction != NULL) {
296 transaction_t *t = jh->b_transaction;
297 tid_t tid = t->t_tid;
298
Johann Lombardi8e85fb32008-01-28 23:58:27 -0500299 transaction->t_chp_stats.cs_forced_to_close++;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700300 spin_unlock(&journal->j_list_lock);
301 jbd_unlock_bh_state(bh);
Theodore Ts'o5c2178e2010-10-27 21:30:04 -0400302 if (unlikely(journal->j_flags & JBD2_UNMOUNT))
303 /*
304 * The journal thread is dead; so starting and
305 * waiting for a commit to finish will cause
306 * us to wait for a _very_ long time.
307 */
308 printk(KERN_ERR "JBD2: %s: "
309 "Waiting for Godot: block %llu\n",
310 journal->j_devname,
311 (unsigned long long) bh->b_blocknr);
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700312 jbd2_log_start_commit(journal, tid);
313 jbd2_log_wait_commit(journal, tid);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700314 ret = 1;
315 } else if (!buffer_dirty(bh)) {
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400316 ret = 1;
317 if (unlikely(buffer_write_io_error(bh)))
318 ret = -EIO;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700319 J_ASSERT_JH(jh, !buffer_jbddirty(bh));
320 BUFFER_TRACE(bh, "remove from checkpoint");
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700321 __jbd2_journal_remove_checkpoint(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700322 spin_unlock(&journal->j_list_lock);
323 jbd_unlock_bh_state(bh);
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700324 jbd2_journal_remove_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700325 __brelse(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700326 } else {
327 /*
328 * Important: we are about to write the buffer, and
329 * possibly block, while still holding the journal lock.
330 * We cannot afford to let the transaction logic start
331 * messing around with this buffer before we write it to
332 * disk, as that would break recoverability.
333 */
334 BUFFER_TRACE(bh, "queue");
335 get_bh(bh);
336 J_ASSERT_BH(bh, !buffer_jwrite(bh));
337 set_buffer_jwrite(bh);
Theodore Ts'o1a0d3782008-11-05 00:09:22 -0500338 journal->j_chkpt_bhs[*batch_count] = bh;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700339 __buffer_relink_io(jh);
340 jbd_unlock_bh_state(bh);
Johann Lombardi8e85fb32008-01-28 23:58:27 -0500341 transaction->t_chp_stats.cs_written++;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700342 (*batch_count)++;
Theodore Ts'o1a0d3782008-11-05 00:09:22 -0500343 if (*batch_count == JBD2_NR_BATCH) {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700344 spin_unlock(&journal->j_list_lock);
Theodore Ts'o1a0d3782008-11-05 00:09:22 -0500345 __flush_batch(journal, batch_count);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700346 ret = 1;
347 }
348 }
349 return ret;
350}
351
352/*
353 * Perform an actual checkpoint. We take the first transaction on the
354 * list of transactions to be checkpointed and send all its buffers
355 * to disk. We submit larger chunks of data at once.
356 *
357 * The journal should be locked before calling this function.
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400358 * Called with j_checkpoint_mutex held.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700359 */
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700360int jbd2_log_do_checkpoint(journal_t *journal)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700361{
362 transaction_t *transaction;
363 tid_t this_tid;
364 int result;
365
366 jbd_debug(1, "Start checkpoint\n");
367
368 /*
369 * First thing: if there are any transactions in the log which
370 * don't need checkpointing, just eliminate them from the
371 * journal straight away.
372 */
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700373 result = jbd2_cleanup_journal_tail(journal);
Theodore Ts'o879c5e62009-06-17 11:47:48 -0400374 trace_jbd2_checkpoint(journal, result);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700375 jbd_debug(1, "cleanup_journal_tail returned %d\n", result);
376 if (result <= 0)
377 return result;
378
379 /*
380 * OK, we need to start writing disk blocks. Take one transaction
381 * and write it.
382 */
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400383 result = 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700384 spin_lock(&journal->j_list_lock);
385 if (!journal->j_checkpoint_transactions)
386 goto out;
387 transaction = journal->j_checkpoint_transactions;
Johann Lombardi8e85fb32008-01-28 23:58:27 -0500388 if (transaction->t_chp_stats.cs_chp_time == 0)
389 transaction->t_chp_stats.cs_chp_time = jiffies;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700390 this_tid = transaction->t_tid;
391restart:
392 /*
393 * If someone cleaned up this transaction while we slept, we're
394 * done (maybe it's a new transaction, but it fell at the same
395 * address).
396 */
397 if (journal->j_checkpoint_transactions == transaction &&
398 transaction->t_tid == this_tid) {
399 int batch_count = 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700400 struct journal_head *jh;
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400401 int retry = 0, err;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700402
403 while (!retry && transaction->t_checkpoint_list) {
404 struct buffer_head *bh;
405
406 jh = transaction->t_checkpoint_list;
407 bh = jh2bh(jh);
408 if (!jbd_trylock_bh_state(bh)) {
409 jbd_sync_bh(journal, bh);
410 retry = 1;
411 break;
412 }
Theodore Ts'o1a0d3782008-11-05 00:09:22 -0500413 retry = __process_buffer(journal, jh, &batch_count,
Johann Lombardi8e85fb32008-01-28 23:58:27 -0500414 transaction);
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400415 if (retry < 0 && !result)
416 result = retry;
Nick Piggin95c354f2008-01-30 13:31:20 +0100417 if (!retry && (need_resched() ||
418 spin_needbreak(&journal->j_list_lock))) {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700419 spin_unlock(&journal->j_list_lock);
420 retry = 1;
421 break;
422 }
423 }
424
425 if (batch_count) {
426 if (!retry) {
427 spin_unlock(&journal->j_list_lock);
428 retry = 1;
429 }
Theodore Ts'o1a0d3782008-11-05 00:09:22 -0500430 __flush_batch(journal, &batch_count);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700431 }
432
433 if (retry) {
434 spin_lock(&journal->j_list_lock);
435 goto restart;
436 }
437 /*
438 * Now we have cleaned up the first transaction's checkpoint
439 * list. Let's clean up the second one
440 */
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400441 err = __wait_cp_io(journal, transaction);
442 if (!result)
443 result = err;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700444 }
445out:
446 spin_unlock(&journal->j_list_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700447 if (result < 0)
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400448 jbd2_journal_abort(journal, result);
449 else
450 result = jbd2_cleanup_journal_tail(journal);
451
452 return (result < 0) ? result : 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700453}
454
455/*
456 * Check the list of checkpoint transactions for the journal to see if
457 * we have already got rid of any since the last update of the log tail
458 * in the journal superblock. If so, we can instantly roll the
459 * superblock forward to remove those transactions from the log.
460 *
461 * Return <0 on error, 0 on success, 1 if there was nothing to clean up.
462 *
463 * Called with the journal lock held.
464 *
465 * This is the only part of the journaling code which really needs to be
466 * aware of transaction aborts. Checkpointing involves writing to the
467 * main filesystem area rather than to the journal, so it can proceed
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400468 * even in abort state, but we must not update the super block if
469 * checkpointing may have failed. Otherwise, we would lose some metadata
470 * buffers which should be written-back to the filesystem.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700471 */
472
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700473int jbd2_cleanup_journal_tail(journal_t *journal)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700474{
475 transaction_t * transaction;
476 tid_t first_tid;
477 unsigned long blocknr, freed;
478
Hidehiro Kawai44519fa2008-10-10 20:29:13 -0400479 if (is_journal_aborted(journal))
480 return 1;
481
Dave Kleikamp470decc2006-10-11 01:20:57 -0700482 /* OK, work out the oldest transaction remaining in the log, and
483 * the log block it starts at.
484 *
485 * If the log is now empty, we need to work out which is the
486 * next transaction ID we will write, and where it will
487 * start. */
488
Theodore Ts'oa931da62010-08-03 21:35:12 -0400489 write_lock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700490 spin_lock(&journal->j_list_lock);
491 transaction = journal->j_checkpoint_transactions;
492 if (transaction) {
493 first_tid = transaction->t_tid;
494 blocknr = transaction->t_log_start;
495 } else if ((transaction = journal->j_committing_transaction) != NULL) {
496 first_tid = transaction->t_tid;
497 blocknr = transaction->t_log_start;
498 } else if ((transaction = journal->j_running_transaction) != NULL) {
499 first_tid = transaction->t_tid;
500 blocknr = journal->j_head;
501 } else {
502 first_tid = journal->j_transaction_sequence;
503 blocknr = journal->j_head;
504 }
505 spin_unlock(&journal->j_list_lock);
506 J_ASSERT(blocknr != 0);
507
508 /* If the oldest pinned transaction is at the tail of the log
509 already then there's not much we can do right now. */
510 if (journal->j_tail_sequence == first_tid) {
Theodore Ts'oa931da62010-08-03 21:35:12 -0400511 write_unlock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700512 return 1;
513 }
514
515 /* OK, update the superblock to recover the freed space.
516 * Physical blocks come first: have we wrapped beyond the end of
517 * the log? */
518 freed = blocknr - journal->j_tail;
519 if (blocknr < journal->j_tail)
520 freed = freed + journal->j_last - journal->j_first;
521
Theodore Ts'o71f2be22009-12-23 07:45:44 -0500522 trace_jbd2_cleanup_journal_tail(journal, first_tid, blocknr, freed);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700523 jbd_debug(1,
524 "Cleaning journal tail from %d to %d (offset %lu), "
525 "freeing %lu\n",
526 journal->j_tail_sequence, first_tid, blocknr, freed);
527
528 journal->j_free += freed;
529 journal->j_tail_sequence = first_tid;
530 journal->j_tail = blocknr;
Theodore Ts'oa931da62010-08-03 21:35:12 -0400531 write_unlock(&journal->j_state_lock);
Theodore Ts'occ3e1be2009-12-23 06:52:08 -0500532
533 /*
534 * If there is an external journal, we need to make sure that
535 * any data blocks that were recently written out --- perhaps
536 * by jbd2_log_do_checkpoint() --- are flushed out before we
537 * drop the transactions from the external journal. It's
538 * unlikely this will be necessary, especially with a
539 * appropriately sized journal, but we need this to guarantee
540 * correctness. Fortunately jbd2_cleanup_journal_tail()
541 * doesn't get called all that often.
542 */
543 if ((journal->j_fs_dev != journal->j_dev) &&
544 (journal->j_flags & JBD2_BARRIER))
Christoph Hellwigdd3932e2010-09-16 20:51:46 +0200545 blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700546 if (!(journal->j_flags & JBD2_ABORT))
547 jbd2_journal_update_superblock(journal, 1);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700548 return 0;
549}
550
551
552/* Checkpoint list management */
553
554/*
555 * journal_clean_one_cp_list
556 *
557 * Find all the written-back checkpoint buffers in the given list and release them.
558 *
559 * Called with the journal locked.
560 * Called with j_list_lock held.
561 * Returns number of bufers reaped (for debug)
562 */
563
564static int journal_clean_one_cp_list(struct journal_head *jh, int *released)
565{
566 struct journal_head *last_jh;
567 struct journal_head *next_jh = jh;
568 int ret, freed = 0;
569
570 *released = 0;
571 if (!jh)
572 return 0;
573
574 last_jh = jh->b_cpprev;
575 do {
576 jh = next_jh;
577 next_jh = jh->b_cpnext;
578 /* Use trylock because of the ranking */
579 if (jbd_trylock_bh_state(jh2bh(jh))) {
580 ret = __try_to_free_cp_buf(jh);
581 if (ret) {
582 freed++;
583 if (ret == 2) {
584 *released = 1;
585 return freed;
586 }
587 }
588 }
589 /*
590 * This function only frees up some memory
591 * if possible so we dont have an obligation
592 * to finish processing. Bail out if preemption
593 * requested:
594 */
595 if (need_resched())
596 return freed;
597 } while (jh != last_jh);
598
599 return freed;
600}
601
602/*
603 * journal_clean_checkpoint_list
604 *
605 * Find all the written-back checkpoint buffers in the journal and release them.
606 *
607 * Called with the journal locked.
608 * Called with j_list_lock held.
609 * Returns number of buffers reaped (for debug)
610 */
611
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700612int __jbd2_journal_clean_checkpoint_list(journal_t *journal)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700613{
614 transaction_t *transaction, *last_transaction, *next_transaction;
615 int ret = 0;
616 int released;
617
618 transaction = journal->j_checkpoint_transactions;
619 if (!transaction)
620 goto out;
621
622 last_transaction = transaction->t_cpprev;
623 next_transaction = transaction;
624 do {
625 transaction = next_transaction;
626 next_transaction = transaction->t_cpnext;
627 ret += journal_clean_one_cp_list(transaction->
628 t_checkpoint_list, &released);
629 /*
630 * This function only frees up some memory if possible so we
631 * dont have an obligation to finish processing. Bail out if
632 * preemption requested:
633 */
634 if (need_resched())
635 goto out;
636 if (released)
637 continue;
638 /*
639 * It is essential that we are as careful as in the case of
640 * t_checkpoint_list with removing the buffer from the list as
641 * we can possibly see not yet submitted buffers on io_list
642 */
643 ret += journal_clean_one_cp_list(transaction->
644 t_checkpoint_io_list, &released);
645 if (need_resched())
646 goto out;
647 } while (transaction != last_transaction);
648out:
649 return ret;
650}
651
652/*
653 * journal_remove_checkpoint: called after a buffer has been committed
654 * to disk (either by being write-back flushed to disk, or being
655 * committed to the log).
656 *
657 * We cannot safely clean a transaction out of the log until all of the
658 * buffer updates committed in that transaction have safely been stored
659 * elsewhere on disk. To achieve this, all of the buffers in a
660 * transaction need to be maintained on the transaction's checkpoint
661 * lists until they have been rewritten, at which point this function is
662 * called to remove the buffer from the existing transaction's
663 * checkpoint lists.
664 *
665 * The function returns 1 if it frees the transaction, 0 otherwise.
666 *
667 * This function is called with the journal locked.
668 * This function is called with j_list_lock held.
669 * This function is called with jbd_lock_bh_state(jh2bh(jh))
670 */
671
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700672int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700673{
Theodore Ts'obf699322009-09-30 00:32:06 -0400674 struct transaction_chp_stats_s *stats;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700675 transaction_t *transaction;
676 journal_t *journal;
677 int ret = 0;
678
679 JBUFFER_TRACE(jh, "entry");
680
681 if ((transaction = jh->b_cp_transaction) == NULL) {
682 JBUFFER_TRACE(jh, "not on transaction");
683 goto out;
684 }
685 journal = transaction->t_journal;
686
687 __buffer_unlink(jh);
688 jh->b_cp_transaction = NULL;
689
690 if (transaction->t_checkpoint_list != NULL ||
691 transaction->t_checkpoint_io_list != NULL)
692 goto out;
693 JBUFFER_TRACE(jh, "transaction has no more buffers");
694
695 /*
696 * There is one special case to worry about: if we have just pulled the
Jan Karaf5a7a6b2008-01-28 23:58:27 -0500697 * buffer off a running or committing transaction's checkpoing list,
698 * then even if the checkpoint list is empty, the transaction obviously
699 * cannot be dropped!
Dave Kleikamp470decc2006-10-11 01:20:57 -0700700 *
Jan Karaf5a7a6b2008-01-28 23:58:27 -0500701 * The locking here around t_state is a bit sleazy.
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700702 * See the comment at the end of jbd2_journal_commit_transaction().
Dave Kleikamp470decc2006-10-11 01:20:57 -0700703 */
Jan Karaf5a7a6b2008-01-28 23:58:27 -0500704 if (transaction->t_state != T_FINISHED) {
705 JBUFFER_TRACE(jh, "belongs to running/committing transaction");
Dave Kleikamp470decc2006-10-11 01:20:57 -0700706 goto out;
707 }
708
709 /* OK, that was the last buffer for the transaction: we can now
710 safely remove this transaction from the log */
Theodore Ts'obf699322009-09-30 00:32:06 -0400711 stats = &transaction->t_chp_stats;
712 if (stats->cs_chp_time)
713 stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time,
714 jiffies);
715 trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev,
716 transaction->t_tid, stats);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700717
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700718 __jbd2_journal_drop_transaction(journal, transaction);
Aneesh Kumar K.Vfb684072008-11-06 17:50:21 -0500719 kfree(transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700720
721 /* Just in case anybody was waiting for more transactions to be
722 checkpointed... */
723 wake_up(&journal->j_wait_logspace);
724 ret = 1;
725out:
726 JBUFFER_TRACE(jh, "exit");
727 return ret;
728}
729
730/*
731 * journal_insert_checkpoint: put a committed buffer onto a checkpoint
732 * list so that we know when it is safe to clean the transaction out of
733 * the log.
734 *
735 * Called with the journal locked.
736 * Called with j_list_lock held.
737 */
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700738void __jbd2_journal_insert_checkpoint(struct journal_head *jh,
Dave Kleikamp470decc2006-10-11 01:20:57 -0700739 transaction_t *transaction)
740{
741 JBUFFER_TRACE(jh, "entry");
742 J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh)));
743 J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
744
745 jh->b_cp_transaction = transaction;
746
747 if (!transaction->t_checkpoint_list) {
748 jh->b_cpnext = jh->b_cpprev = jh;
749 } else {
750 jh->b_cpnext = transaction->t_checkpoint_list;
751 jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev;
752 jh->b_cpprev->b_cpnext = jh;
753 jh->b_cpnext->b_cpprev = jh;
754 }
755 transaction->t_checkpoint_list = jh;
756}
757
758/*
759 * We've finished with this transaction structure: adios...
760 *
761 * The transaction must have no links except for the checkpoint by this
762 * point.
763 *
764 * Called with the journal locked.
765 * Called with j_list_lock held.
766 */
767
Mingming Caof7f4bccb2006-10-11 01:20:59 -0700768void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700769{
770 assert_spin_locked(&journal->j_list_lock);
771 if (transaction->t_cpnext) {
772 transaction->t_cpnext->t_cpprev = transaction->t_cpprev;
773 transaction->t_cpprev->t_cpnext = transaction->t_cpnext;
774 if (journal->j_checkpoint_transactions == transaction)
775 journal->j_checkpoint_transactions =
776 transaction->t_cpnext;
777 if (journal->j_checkpoint_transactions == transaction)
778 journal->j_checkpoint_transactions = NULL;
779 }
780
781 J_ASSERT(transaction->t_state == T_FINISHED);
782 J_ASSERT(transaction->t_buffers == NULL);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700783 J_ASSERT(transaction->t_forget == NULL);
784 J_ASSERT(transaction->t_iobuf_list == NULL);
785 J_ASSERT(transaction->t_shadow_list == NULL);
786 J_ASSERT(transaction->t_log_list == NULL);
787 J_ASSERT(transaction->t_checkpoint_list == NULL);
788 J_ASSERT(transaction->t_checkpoint_io_list == NULL);
Theodore Ts'oa51dca92010-08-02 08:43:25 -0400789 J_ASSERT(atomic_read(&transaction->t_updates) == 0);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700790 J_ASSERT(journal->j_committing_transaction != transaction);
791 J_ASSERT(journal->j_running_transaction != transaction);
792
793 jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700794}