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1da177e4 LT |
1 | /* |
2 | * linux/fs/checkpoint.c | |
3 | * | |
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> | |
22 | #include <linux/jbd.h> | |
23 | #include <linux/errno.h> | |
24 | #include <linux/slab.h> | |
25 | ||
26 | /* | |
7c8903f6 | 27 | * Unlink a buffer from a transaction. |
1da177e4 LT |
28 | * |
29 | * Called with j_list_lock held. | |
30 | */ | |
31 | ||
7c8903f6 | 32 | static inline void __buffer_unlink(struct journal_head *jh) |
1da177e4 LT |
33 | { |
34 | transaction_t *transaction; | |
35 | ||
36 | transaction = jh->b_cp_transaction; | |
7c8903f6 | 37 | jh->b_cp_transaction = NULL; |
1da177e4 LT |
38 | |
39 | jh->b_cpnext->b_cpprev = jh->b_cpprev; | |
40 | jh->b_cpprev->b_cpnext = jh->b_cpnext; | |
7c8903f6 | 41 | if (transaction->t_checkpoint_list == jh) |
1da177e4 | 42 | transaction->t_checkpoint_list = jh->b_cpnext; |
7c8903f6 MF |
43 | if (transaction->t_checkpoint_list == jh) |
44 | transaction->t_checkpoint_list = NULL; | |
1da177e4 LT |
45 | } |
46 | ||
47 | /* | |
48 | * Try to release a checkpointed buffer from its transaction. | |
7c8903f6 | 49 | * Returns 1 if we released it. |
1da177e4 LT |
50 | * Requires j_list_lock |
51 | * Called under jbd_lock_bh_state(jh2bh(jh)), and drops it | |
52 | */ | |
53 | static int __try_to_free_cp_buf(struct journal_head *jh) | |
54 | { | |
55 | int ret = 0; | |
56 | struct buffer_head *bh = jh2bh(jh); | |
57 | ||
58 | if (jh->b_jlist == BJ_None && !buffer_locked(bh) && !buffer_dirty(bh)) { | |
59 | JBUFFER_TRACE(jh, "remove from checkpoint list"); | |
7c8903f6 | 60 | __journal_remove_checkpoint(jh); |
1da177e4 LT |
61 | jbd_unlock_bh_state(bh); |
62 | journal_remove_journal_head(bh); | |
63 | BUFFER_TRACE(bh, "release"); | |
64 | __brelse(bh); | |
7c8903f6 | 65 | ret = 1; |
1da177e4 LT |
66 | } else { |
67 | jbd_unlock_bh_state(bh); | |
68 | } | |
69 | return ret; | |
70 | } | |
71 | ||
72 | /* | |
73 | * __log_wait_for_space: wait until there is space in the journal. | |
74 | * | |
75 | * Called under j-state_lock *only*. It will be unlocked if we have to wait | |
76 | * for a checkpoint to free up some space in the log. | |
77 | */ | |
78 | void __log_wait_for_space(journal_t *journal) | |
79 | { | |
80 | int nblocks; | |
81 | assert_spin_locked(&journal->j_state_lock); | |
82 | ||
83 | nblocks = jbd_space_needed(journal); | |
84 | while (__log_space_left(journal) < nblocks) { | |
85 | if (journal->j_flags & JFS_ABORT) | |
86 | return; | |
87 | spin_unlock(&journal->j_state_lock); | |
2c68ee75 | 88 | mutex_lock(&journal->j_checkpoint_mutex); |
1da177e4 LT |
89 | |
90 | /* | |
91 | * Test again, another process may have checkpointed while we | |
92 | * were waiting for the checkpoint lock | |
93 | */ | |
94 | spin_lock(&journal->j_state_lock); | |
95 | nblocks = jbd_space_needed(journal); | |
96 | if (__log_space_left(journal) < nblocks) { | |
97 | spin_unlock(&journal->j_state_lock); | |
98 | log_do_checkpoint(journal); | |
99 | spin_lock(&journal->j_state_lock); | |
100 | } | |
2c68ee75 | 101 | mutex_unlock(&journal->j_checkpoint_mutex); |
1da177e4 LT |
102 | } |
103 | } | |
104 | ||
105 | /* | |
106 | * We were unable to perform jbd_trylock_bh_state() inside j_list_lock. | |
107 | * The caller must restart a list walk. Wait for someone else to run | |
108 | * jbd_unlock_bh_state(). | |
109 | */ | |
110 | static void jbd_sync_bh(journal_t *journal, struct buffer_head *bh) | |
111 | { | |
112 | get_bh(bh); | |
113 | spin_unlock(&journal->j_list_lock); | |
114 | jbd_lock_bh_state(bh); | |
115 | jbd_unlock_bh_state(bh); | |
116 | put_bh(bh); | |
117 | } | |
118 | ||
119 | /* | |
7c8903f6 MF |
120 | * Clean up a transaction's checkpoint list. |
121 | * | |
122 | * We wait for any pending IO to complete and make sure any clean | |
123 | * buffers are removed from the transaction. | |
124 | * | |
125 | * Return 1 if we performed any actions which might have destroyed the | |
126 | * checkpoint. (journal_remove_checkpoint() deletes the transaction when | |
127 | * the last checkpoint buffer is cleansed) | |
1da177e4 LT |
128 | * |
129 | * Called with j_list_lock held. | |
130 | */ | |
7c8903f6 | 131 | static int __cleanup_transaction(journal_t *journal, transaction_t *transaction) |
1da177e4 | 132 | { |
7c8903f6 | 133 | struct journal_head *jh, *next_jh, *last_jh; |
1da177e4 | 134 | struct buffer_head *bh; |
7c8903f6 MF |
135 | int ret = 0; |
136 | ||
137 | assert_spin_locked(&journal->j_list_lock); | |
138 | jh = transaction->t_checkpoint_list; | |
139 | if (!jh) | |
140 | return 0; | |
141 | ||
142 | last_jh = jh->b_cpprev; | |
143 | next_jh = jh; | |
144 | do { | |
145 | jh = next_jh; | |
1da177e4 LT |
146 | bh = jh2bh(jh); |
147 | if (buffer_locked(bh)) { | |
148 | atomic_inc(&bh->b_count); | |
149 | spin_unlock(&journal->j_list_lock); | |
150 | wait_on_buffer(bh); | |
151 | /* the journal_head may have gone by now */ | |
152 | BUFFER_TRACE(bh, "brelse"); | |
153 | __brelse(bh); | |
7c8903f6 | 154 | goto out_return_1; |
1da177e4 | 155 | } |
7c8903f6 | 156 | |
1da177e4 | 157 | /* |
7c8903f6 | 158 | * This is foul |
1da177e4 | 159 | */ |
7c8903f6 MF |
160 | if (!jbd_trylock_bh_state(bh)) { |
161 | jbd_sync_bh(journal, bh); | |
162 | goto out_return_1; | |
163 | } | |
164 | ||
165 | if (jh->b_transaction != NULL) { | |
166 | transaction_t *t = jh->b_transaction; | |
167 | tid_t tid = t->t_tid; | |
168 | ||
169 | spin_unlock(&journal->j_list_lock); | |
170 | jbd_unlock_bh_state(bh); | |
171 | log_start_commit(journal, tid); | |
172 | log_wait_commit(journal, tid); | |
173 | goto out_return_1; | |
174 | } | |
175 | ||
176 | /* | |
177 | * AKPM: I think the buffer_jbddirty test is redundant - it | |
178 | * shouldn't have NULL b_transaction? | |
179 | */ | |
180 | next_jh = jh->b_cpnext; | |
181 | if (!buffer_dirty(bh) && !buffer_jbddirty(bh)) { | |
182 | BUFFER_TRACE(bh, "remove from checkpoint"); | |
183 | __journal_remove_checkpoint(jh); | |
184 | jbd_unlock_bh_state(bh); | |
185 | journal_remove_journal_head(bh); | |
186 | __brelse(bh); | |
187 | ret = 1; | |
188 | } else { | |
189 | jbd_unlock_bh_state(bh); | |
190 | } | |
191 | } while (jh != last_jh); | |
192 | ||
193 | return ret; | |
194 | out_return_1: | |
195 | spin_lock(&journal->j_list_lock); | |
196 | return 1; | |
1da177e4 LT |
197 | } |
198 | ||
199 | #define NR_BATCH 64 | |
200 | ||
201 | static void | |
202 | __flush_batch(journal_t *journal, struct buffer_head **bhs, int *batch_count) | |
203 | { | |
204 | int i; | |
205 | ||
7c8903f6 | 206 | spin_unlock(&journal->j_list_lock); |
26707699 | 207 | ll_rw_block(SWRITE, *batch_count, bhs); |
7c8903f6 | 208 | spin_lock(&journal->j_list_lock); |
1da177e4 LT |
209 | for (i = 0; i < *batch_count; i++) { |
210 | struct buffer_head *bh = bhs[i]; | |
211 | clear_buffer_jwrite(bh); | |
212 | BUFFER_TRACE(bh, "brelse"); | |
213 | __brelse(bh); | |
214 | } | |
215 | *batch_count = 0; | |
216 | } | |
217 | ||
218 | /* | |
219 | * Try to flush one buffer from the checkpoint list to disk. | |
220 | * | |
221 | * Return 1 if something happened which requires us to abort the current | |
222 | * scan of the checkpoint list. | |
223 | * | |
7c8903f6 | 224 | * Called with j_list_lock held. |
1da177e4 LT |
225 | * Called under jbd_lock_bh_state(jh2bh(jh)), and drops it |
226 | */ | |
7c8903f6 MF |
227 | static int __flush_buffer(journal_t *journal, struct journal_head *jh, |
228 | struct buffer_head **bhs, int *batch_count, | |
229 | int *drop_count) | |
1da177e4 LT |
230 | { |
231 | struct buffer_head *bh = jh2bh(jh); | |
232 | int ret = 0; | |
233 | ||
7c8903f6 MF |
234 | if (buffer_dirty(bh) && !buffer_locked(bh) && jh->b_jlist == BJ_None) { |
235 | J_ASSERT_JH(jh, jh->b_transaction == NULL); | |
1da177e4 LT |
236 | |
237 | /* | |
238 | * Important: we are about to write the buffer, and | |
239 | * possibly block, while still holding the journal lock. | |
240 | * We cannot afford to let the transaction logic start | |
241 | * messing around with this buffer before we write it to | |
242 | * disk, as that would break recoverability. | |
243 | */ | |
244 | BUFFER_TRACE(bh, "queue"); | |
245 | get_bh(bh); | |
246 | J_ASSERT_BH(bh, !buffer_jwrite(bh)); | |
247 | set_buffer_jwrite(bh); | |
248 | bhs[*batch_count] = bh; | |
249 | jbd_unlock_bh_state(bh); | |
250 | (*batch_count)++; | |
251 | if (*batch_count == NR_BATCH) { | |
252 | __flush_batch(journal, bhs, batch_count); | |
253 | ret = 1; | |
254 | } | |
7c8903f6 MF |
255 | } else { |
256 | int last_buffer = 0; | |
257 | if (jh->b_cpnext == jh) { | |
258 | /* We may be about to drop the transaction. Tell the | |
259 | * caller that the lists have changed. | |
260 | */ | |
261 | last_buffer = 1; | |
262 | } | |
263 | if (__try_to_free_cp_buf(jh)) { | |
264 | (*drop_count)++; | |
265 | ret = last_buffer; | |
266 | } | |
1da177e4 LT |
267 | } |
268 | return ret; | |
269 | } | |
270 | ||
271 | /* | |
7c8903f6 MF |
272 | * Perform an actual checkpoint. We don't write out only enough to |
273 | * satisfy the current blocked requests: rather we submit a reasonably | |
274 | * sized chunk of the outstanding data to disk at once for | |
275 | * efficiency. __log_wait_for_space() will retry if we didn't free enough. | |
1da177e4 | 276 | * |
7c8903f6 MF |
277 | * However, we _do_ take into account the amount requested so that once |
278 | * the IO has been queued, we can return as soon as enough of it has | |
279 | * completed to disk. | |
280 | * | |
1da177e4 LT |
281 | * The journal should be locked before calling this function. |
282 | */ | |
283 | int log_do_checkpoint(journal_t *journal) | |
284 | { | |
285 | int result; | |
7c8903f6 MF |
286 | int batch_count = 0; |
287 | struct buffer_head *bhs[NR_BATCH]; | |
1da177e4 LT |
288 | |
289 | jbd_debug(1, "Start checkpoint\n"); | |
290 | ||
291 | /* | |
292 | * First thing: if there are any transactions in the log which | |
293 | * don't need checkpointing, just eliminate them from the | |
294 | * journal straight away. | |
295 | */ | |
296 | result = cleanup_journal_tail(journal); | |
297 | jbd_debug(1, "cleanup_journal_tail returned %d\n", result); | |
298 | if (result <= 0) | |
299 | return result; | |
300 | ||
301 | /* | |
7c8903f6 MF |
302 | * OK, we need to start writing disk blocks. Try to free up a |
303 | * quarter of the log in a single checkpoint if we can. | |
1da177e4 LT |
304 | */ |
305 | /* | |
7c8903f6 MF |
306 | * AKPM: check this code. I had a feeling a while back that it |
307 | * degenerates into a busy loop at unmount time. | |
1da177e4 | 308 | */ |
7c8903f6 MF |
309 | spin_lock(&journal->j_list_lock); |
310 | while (journal->j_checkpoint_transactions) { | |
311 | transaction_t *transaction; | |
312 | struct journal_head *jh, *last_jh, *next_jh; | |
313 | int drop_count = 0; | |
314 | int cleanup_ret, retry = 0; | |
315 | tid_t this_tid; | |
316 | ||
317 | transaction = journal->j_checkpoint_transactions; | |
318 | this_tid = transaction->t_tid; | |
319 | jh = transaction->t_checkpoint_list; | |
320 | last_jh = jh->b_cpprev; | |
321 | next_jh = jh; | |
322 | do { | |
1da177e4 LT |
323 | struct buffer_head *bh; |
324 | ||
7c8903f6 MF |
325 | jh = next_jh; |
326 | next_jh = jh->b_cpnext; | |
1da177e4 LT |
327 | bh = jh2bh(jh); |
328 | if (!jbd_trylock_bh_state(bh)) { | |
329 | jbd_sync_bh(journal, bh); | |
7c8903f6 | 330 | spin_lock(&journal->j_list_lock); |
1da177e4 LT |
331 | retry = 1; |
332 | break; | |
333 | } | |
7c8903f6 MF |
334 | retry = __flush_buffer(journal, jh, bhs, &batch_count, &drop_count); |
335 | if (cond_resched_lock(&journal->j_list_lock)) { | |
1da177e4 LT |
336 | retry = 1; |
337 | break; | |
338 | } | |
7c8903f6 | 339 | } while (jh != last_jh && !retry); |
1da177e4 | 340 | |
00ea8145 | 341 | if (batch_count) { |
1da177e4 | 342 | __flush_batch(journal, bhs, &batch_count); |
7c8903f6 | 343 | retry = 1; |
00ea8145 | 344 | } |
1da177e4 LT |
345 | |
346 | /* | |
7c8903f6 MF |
347 | * If someone cleaned up this transaction while we slept, we're |
348 | * done | |
349 | */ | |
350 | if (journal->j_checkpoint_transactions != transaction) | |
351 | break; | |
352 | if (retry) | |
353 | continue; | |
354 | /* | |
355 | * Maybe it's a new transaction, but it fell at the same | |
356 | * address | |
1da177e4 | 357 | */ |
7c8903f6 MF |
358 | if (transaction->t_tid != this_tid) |
359 | continue; | |
360 | /* | |
361 | * We have walked the whole transaction list without | |
362 | * finding anything to write to disk. We had better be | |
363 | * able to make some progress or we are in trouble. | |
364 | */ | |
365 | cleanup_ret = __cleanup_transaction(journal, transaction); | |
366 | J_ASSERT(drop_count != 0 || cleanup_ret != 0); | |
367 | if (journal->j_checkpoint_transactions != transaction) | |
368 | break; | |
1da177e4 LT |
369 | } |
370 | spin_unlock(&journal->j_list_lock); | |
371 | result = cleanup_journal_tail(journal); | |
372 | if (result < 0) | |
373 | return result; | |
7c8903f6 | 374 | |
1da177e4 LT |
375 | return 0; |
376 | } | |
377 | ||
378 | /* | |
379 | * Check the list of checkpoint transactions for the journal to see if | |
380 | * we have already got rid of any since the last update of the log tail | |
381 | * in the journal superblock. If so, we can instantly roll the | |
382 | * superblock forward to remove those transactions from the log. | |
383 | * | |
384 | * Return <0 on error, 0 on success, 1 if there was nothing to clean up. | |
385 | * | |
386 | * Called with the journal lock held. | |
387 | * | |
388 | * This is the only part of the journaling code which really needs to be | |
389 | * aware of transaction aborts. Checkpointing involves writing to the | |
390 | * main filesystem area rather than to the journal, so it can proceed | |
391 | * even in abort state, but we must not update the journal superblock if | |
392 | * we have an abort error outstanding. | |
393 | */ | |
394 | ||
395 | int cleanup_journal_tail(journal_t *journal) | |
396 | { | |
397 | transaction_t * transaction; | |
398 | tid_t first_tid; | |
399 | unsigned long blocknr, freed; | |
400 | ||
401 | /* OK, work out the oldest transaction remaining in the log, and | |
402 | * the log block it starts at. | |
403 | * | |
404 | * If the log is now empty, we need to work out which is the | |
405 | * next transaction ID we will write, and where it will | |
406 | * start. */ | |
407 | ||
408 | spin_lock(&journal->j_state_lock); | |
409 | spin_lock(&journal->j_list_lock); | |
410 | transaction = journal->j_checkpoint_transactions; | |
411 | if (transaction) { | |
412 | first_tid = transaction->t_tid; | |
413 | blocknr = transaction->t_log_start; | |
414 | } else if ((transaction = journal->j_committing_transaction) != NULL) { | |
415 | first_tid = transaction->t_tid; | |
416 | blocknr = transaction->t_log_start; | |
417 | } else if ((transaction = journal->j_running_transaction) != NULL) { | |
418 | first_tid = transaction->t_tid; | |
419 | blocknr = journal->j_head; | |
420 | } else { | |
421 | first_tid = journal->j_transaction_sequence; | |
422 | blocknr = journal->j_head; | |
423 | } | |
424 | spin_unlock(&journal->j_list_lock); | |
425 | J_ASSERT(blocknr != 0); | |
426 | ||
427 | /* If the oldest pinned transaction is at the tail of the log | |
428 | already then there's not much we can do right now. */ | |
429 | if (journal->j_tail_sequence == first_tid) { | |
430 | spin_unlock(&journal->j_state_lock); | |
431 | return 1; | |
432 | } | |
433 | ||
434 | /* OK, update the superblock to recover the freed space. | |
435 | * Physical blocks come first: have we wrapped beyond the end of | |
436 | * the log? */ | |
437 | freed = blocknr - journal->j_tail; | |
438 | if (blocknr < journal->j_tail) | |
439 | freed = freed + journal->j_last - journal->j_first; | |
440 | ||
441 | jbd_debug(1, | |
442 | "Cleaning journal tail from %d to %d (offset %lu), " | |
443 | "freeing %lu\n", | |
444 | journal->j_tail_sequence, first_tid, blocknr, freed); | |
445 | ||
446 | journal->j_free += freed; | |
447 | journal->j_tail_sequence = first_tid; | |
448 | journal->j_tail = blocknr; | |
449 | spin_unlock(&journal->j_state_lock); | |
450 | if (!(journal->j_flags & JFS_ABORT)) | |
451 | journal_update_superblock(journal, 1); | |
452 | return 0; | |
453 | } | |
454 | ||
455 | ||
456 | /* Checkpoint list management */ | |
457 | ||
458 | /* | |
459 | * journal_clean_checkpoint_list | |
460 | * | |
461 | * Find all the written-back checkpoint buffers in the journal and release them. | |
462 | * | |
463 | * Called with the journal locked. | |
464 | * Called with j_list_lock held. | |
7c8903f6 | 465 | * Returns number of bufers reaped (for debug) |
1da177e4 LT |
466 | */ |
467 | ||
468 | int __journal_clean_checkpoint_list(journal_t *journal) | |
469 | { | |
470 | transaction_t *transaction, *last_transaction, *next_transaction; | |
7c8903f6 | 471 | int ret = 0; |
1da177e4 LT |
472 | |
473 | transaction = journal->j_checkpoint_transactions; | |
7c8903f6 | 474 | if (transaction == 0) |
1da177e4 LT |
475 | goto out; |
476 | ||
477 | last_transaction = transaction->t_cpprev; | |
478 | next_transaction = transaction; | |
479 | do { | |
7c8903f6 MF |
480 | struct journal_head *jh; |
481 | ||
1da177e4 LT |
482 | transaction = next_transaction; |
483 | next_transaction = transaction->t_cpnext; | |
7c8903f6 MF |
484 | jh = transaction->t_checkpoint_list; |
485 | if (jh) { | |
486 | struct journal_head *last_jh = jh->b_cpprev; | |
487 | struct journal_head *next_jh = jh; | |
488 | ||
489 | do { | |
490 | jh = next_jh; | |
491 | next_jh = jh->b_cpnext; | |
492 | /* Use trylock because of the ranknig */ | |
493 | if (jbd_trylock_bh_state(jh2bh(jh))) | |
494 | ret += __try_to_free_cp_buf(jh); | |
495 | /* | |
496 | * This function only frees up some memory | |
497 | * if possible so we dont have an obligation | |
498 | * to finish processing. Bail out if preemption | |
499 | * requested: | |
500 | */ | |
501 | if (need_resched()) | |
502 | goto out; | |
503 | } while (jh != last_jh); | |
504 | } | |
1da177e4 LT |
505 | } while (transaction != last_transaction); |
506 | out: | |
507 | return ret; | |
508 | } | |
509 | ||
510 | /* | |
511 | * journal_remove_checkpoint: called after a buffer has been committed | |
512 | * to disk (either by being write-back flushed to disk, or being | |
513 | * committed to the log). | |
514 | * | |
515 | * We cannot safely clean a transaction out of the log until all of the | |
516 | * buffer updates committed in that transaction have safely been stored | |
517 | * elsewhere on disk. To achieve this, all of the buffers in a | |
518 | * transaction need to be maintained on the transaction's checkpoint | |
7c8903f6 | 519 | * list until they have been rewritten, at which point this function is |
1da177e4 | 520 | * called to remove the buffer from the existing transaction's |
7c8903f6 | 521 | * checkpoint list. |
1da177e4 LT |
522 | * |
523 | * This function is called with the journal locked. | |
524 | * This function is called with j_list_lock held. | |
525 | */ | |
526 | ||
7c8903f6 | 527 | void __journal_remove_checkpoint(struct journal_head *jh) |
1da177e4 LT |
528 | { |
529 | transaction_t *transaction; | |
530 | journal_t *journal; | |
531 | ||
532 | JBUFFER_TRACE(jh, "entry"); | |
533 | ||
534 | if ((transaction = jh->b_cp_transaction) == NULL) { | |
535 | JBUFFER_TRACE(jh, "not on transaction"); | |
536 | goto out; | |
537 | } | |
538 | journal = transaction->t_journal; | |
539 | ||
540 | __buffer_unlink(jh); | |
541 | ||
7c8903f6 | 542 | if (transaction->t_checkpoint_list != NULL) |
1da177e4 LT |
543 | goto out; |
544 | JBUFFER_TRACE(jh, "transaction has no more buffers"); | |
545 | ||
546 | /* | |
547 | * There is one special case to worry about: if we have just pulled the | |
548 | * buffer off a committing transaction's forget list, then even if the | |
549 | * checkpoint list is empty, the transaction obviously cannot be | |
550 | * dropped! | |
551 | * | |
552 | * The locking here around j_committing_transaction is a bit sleazy. | |
553 | * See the comment at the end of journal_commit_transaction(). | |
554 | */ | |
555 | if (transaction == journal->j_committing_transaction) { | |
556 | JBUFFER_TRACE(jh, "belongs to committing transaction"); | |
557 | goto out; | |
558 | } | |
559 | ||
560 | /* OK, that was the last buffer for the transaction: we can now | |
561 | safely remove this transaction from the log */ | |
562 | ||
563 | __journal_drop_transaction(journal, transaction); | |
564 | ||
565 | /* Just in case anybody was waiting for more transactions to be | |
566 | checkpointed... */ | |
567 | wake_up(&journal->j_wait_logspace); | |
568 | out: | |
569 | JBUFFER_TRACE(jh, "exit"); | |
570 | } | |
571 | ||
572 | /* | |
573 | * journal_insert_checkpoint: put a committed buffer onto a checkpoint | |
574 | * list so that we know when it is safe to clean the transaction out of | |
575 | * the log. | |
576 | * | |
577 | * Called with the journal locked. | |
578 | * Called with j_list_lock held. | |
579 | */ | |
580 | void __journal_insert_checkpoint(struct journal_head *jh, | |
581 | transaction_t *transaction) | |
582 | { | |
583 | JBUFFER_TRACE(jh, "entry"); | |
584 | J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh))); | |
585 | J_ASSERT_JH(jh, jh->b_cp_transaction == NULL); | |
586 | ||
587 | jh->b_cp_transaction = transaction; | |
588 | ||
589 | if (!transaction->t_checkpoint_list) { | |
590 | jh->b_cpnext = jh->b_cpprev = jh; | |
591 | } else { | |
592 | jh->b_cpnext = transaction->t_checkpoint_list; | |
593 | jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev; | |
594 | jh->b_cpprev->b_cpnext = jh; | |
595 | jh->b_cpnext->b_cpprev = jh; | |
596 | } | |
597 | transaction->t_checkpoint_list = jh; | |
598 | } | |
599 | ||
600 | /* | |
601 | * We've finished with this transaction structure: adios... | |
602 | * | |
603 | * The transaction must have no links except for the checkpoint by this | |
604 | * point. | |
605 | * | |
606 | * Called with the journal locked. | |
607 | * Called with j_list_lock held. | |
608 | */ | |
609 | ||
610 | void __journal_drop_transaction(journal_t *journal, transaction_t *transaction) | |
611 | { | |
612 | assert_spin_locked(&journal->j_list_lock); | |
613 | if (transaction->t_cpnext) { | |
614 | transaction->t_cpnext->t_cpprev = transaction->t_cpprev; | |
615 | transaction->t_cpprev->t_cpnext = transaction->t_cpnext; | |
616 | if (journal->j_checkpoint_transactions == transaction) | |
617 | journal->j_checkpoint_transactions = | |
618 | transaction->t_cpnext; | |
619 | if (journal->j_checkpoint_transactions == transaction) | |
620 | journal->j_checkpoint_transactions = NULL; | |
621 | } | |
622 | ||
623 | J_ASSERT(transaction->t_state == T_FINISHED); | |
624 | J_ASSERT(transaction->t_buffers == NULL); | |
625 | J_ASSERT(transaction->t_sync_datalist == NULL); | |
626 | J_ASSERT(transaction->t_forget == NULL); | |
627 | J_ASSERT(transaction->t_iobuf_list == NULL); | |
628 | J_ASSERT(transaction->t_shadow_list == NULL); | |
629 | J_ASSERT(transaction->t_log_list == NULL); | |
630 | J_ASSERT(transaction->t_checkpoint_list == NULL); | |
631 | J_ASSERT(transaction->t_updates == 0); | |
632 | J_ASSERT(journal->j_committing_transaction != transaction); | |
633 | J_ASSERT(journal->j_running_transaction != transaction); | |
634 | ||
635 | jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid); | |
636 | kfree(transaction); | |
637 | } |