Commit | Line | Data |
---|---|---|
470decc6 | 1 | /* |
58862699 | 2 | * linux/fs/jbd2/checkpoint.c |
470decc6 DK |
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> | |
f7f4bccb | 22 | #include <linux/jbd2.h> |
470decc6 DK |
23 | #include <linux/errno.h> |
24 | #include <linux/slab.h> | |
cc3e1bea | 25 | #include <linux/blkdev.h> |
879c5e6b | 26 | #include <trace/events/jbd2.h> |
470decc6 DK |
27 | |
28 | /* | |
29 | * Unlink a buffer from a transaction checkpoint list. | |
30 | * | |
31 | * Called with j_list_lock held. | |
32 | */ | |
33 | static 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 | */ | |
51 | static 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 | */ | |
68 | static 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 | */ | |
93 | static int __try_to_free_cp_buf(struct journal_head *jh) | |
94 | { | |
95 | int ret = 0; | |
96 | struct buffer_head *bh = jh2bh(jh); | |
97 | ||
44519faf HK |
98 | if (jh->b_jlist == BJ_None && !buffer_locked(bh) && |
99 | !buffer_dirty(bh) && !buffer_write_io_error(bh)) { | |
470decc6 | 100 | JBUFFER_TRACE(jh, "remove from checkpoint list"); |
f7f4bccb | 101 | ret = __jbd2_journal_remove_checkpoint(jh) + 1; |
470decc6 | 102 | jbd_unlock_bh_state(bh); |
f7f4bccb | 103 | jbd2_journal_remove_journal_head(bh); |
470decc6 DK |
104 | BUFFER_TRACE(bh, "release"); |
105 | __brelse(bh); | |
106 | } else { | |
107 | jbd_unlock_bh_state(bh); | |
108 | } | |
109 | return ret; | |
110 | } | |
111 | ||
112 | /* | |
f7f4bccb | 113 | * __jbd2_log_wait_for_space: wait until there is space in the journal. |
470decc6 DK |
114 | * |
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 | */ | |
f7f4bccb | 118 | void __jbd2_log_wait_for_space(journal_t *journal) |
470decc6 | 119 | { |
8c3f25d8 | 120 | int nblocks, space_left; |
470decc6 DK |
121 | assert_spin_locked(&journal->j_state_lock); |
122 | ||
123 | nblocks = jbd_space_needed(journal); | |
f7f4bccb MC |
124 | while (__jbd2_log_space_left(journal) < nblocks) { |
125 | if (journal->j_flags & JBD2_ABORT) | |
470decc6 DK |
126 | return; |
127 | spin_unlock(&journal->j_state_lock); | |
128 | mutex_lock(&journal->j_checkpoint_mutex); | |
129 | ||
130 | /* | |
131 | * Test again, another process may have checkpointed while we | |
23f8b79e | 132 | * were waiting for the checkpoint lock. If there are no |
8c3f25d8 TT |
133 | * 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. | |
470decc6 DK |
140 | */ |
141 | spin_lock(&journal->j_state_lock); | |
23f8b79e | 142 | spin_lock(&journal->j_list_lock); |
470decc6 | 143 | nblocks = jbd_space_needed(journal); |
8c3f25d8 TT |
144 | space_left = __jbd2_log_space_left(journal); |
145 | if (space_left < nblocks) { | |
23f8b79e | 146 | int chkpt = journal->j_checkpoint_transactions != NULL; |
8c3f25d8 | 147 | tid_t tid = 0; |
23f8b79e | 148 | |
8c3f25d8 TT |
149 | if (journal->j_committing_transaction) |
150 | tid = journal->j_committing_transaction->t_tid; | |
23f8b79e | 151 | spin_unlock(&journal->j_list_lock); |
470decc6 | 152 | spin_unlock(&journal->j_state_lock); |
23f8b79e DG |
153 | if (chkpt) { |
154 | jbd2_log_do_checkpoint(journal); | |
8c3f25d8 TT |
155 | } 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); | |
23f8b79e | 160 | } else { |
8c3f25d8 TT |
161 | 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); | |
23f8b79e DG |
168 | jbd2_journal_abort(journal, 0); |
169 | } | |
470decc6 | 170 | spin_lock(&journal->j_state_lock); |
23f8b79e DG |
171 | } else { |
172 | spin_unlock(&journal->j_list_lock); | |
470decc6 DK |
173 | } |
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 | */ | |
183 | static 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 | * | |
44519faf HK |
199 | * Return 0 on success, and return <0 if some buffers have failed |
200 | * to be written out. | |
201 | * | |
470decc6 DK |
202 | * Called with j_list_lock held. |
203 | */ | |
44519faf | 204 | static int __wait_cp_io(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
205 | { |
206 | struct journal_head *jh; | |
207 | struct buffer_head *bh; | |
208 | tid_t this_tid; | |
209 | int released = 0; | |
44519faf | 210 | int ret = 0; |
470decc6 DK |
211 | |
212 | this_tid = transaction->t_tid; | |
213 | restart: | |
214 | /* Did somebody clean up the transaction in the meanwhile? */ | |
215 | if (journal->j_checkpoint_transactions != transaction || | |
216 | transaction->t_tid != this_tid) | |
44519faf | 217 | return ret; |
470decc6 DK |
218 | 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 | } | |
44519faf HK |
237 | if (unlikely(buffer_write_io_error(bh))) |
238 | ret = -EIO; | |
239 | ||
470decc6 DK |
240 | /* |
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 | */ | |
f7f4bccb | 244 | released = __jbd2_journal_remove_checkpoint(jh); |
470decc6 | 245 | jbd_unlock_bh_state(bh); |
f7f4bccb | 246 | jbd2_journal_remove_journal_head(bh); |
470decc6 DK |
247 | __brelse(bh); |
248 | } | |
44519faf HK |
249 | |
250 | return ret; | |
470decc6 DK |
251 | } |
252 | ||
470decc6 | 253 | static void |
1a0d3786 | 254 | __flush_batch(journal_t *journal, int *batch_count) |
470decc6 DK |
255 | { |
256 | int i; | |
257 | ||
1a0d3786 | 258 | ll_rw_block(SWRITE, *batch_count, journal->j_chkpt_bhs); |
470decc6 | 259 | for (i = 0; i < *batch_count; i++) { |
1a0d3786 | 260 | struct buffer_head *bh = journal->j_chkpt_bhs[i]; |
470decc6 DK |
261 | clear_buffer_jwrite(bh); |
262 | BUFFER_TRACE(bh, "brelse"); | |
263 | __brelse(bh); | |
264 | } | |
265 | *batch_count = 0; | |
266 | } | |
267 | ||
268 | /* | |
269 | * Try to flush one buffer from the checkpoint list to disk. | |
270 | * | |
271 | * Return 1 if something happened which requires us to abort the current | |
44519faf HK |
272 | * scan of the checkpoint list. Return <0 if the buffer has failed to |
273 | * be written out. | |
470decc6 DK |
274 | * |
275 | * Called with j_list_lock held and drops it if 1 is returned | |
276 | * Called under jbd_lock_bh_state(jh2bh(jh)), and drops it | |
277 | */ | |
278 | static int __process_buffer(journal_t *journal, struct journal_head *jh, | |
1a0d3786 | 279 | int *batch_count, transaction_t *transaction) |
470decc6 DK |
280 | { |
281 | struct buffer_head *bh = jh2bh(jh); | |
282 | int ret = 0; | |
283 | ||
284 | if (buffer_locked(bh)) { | |
285 | atomic_inc(&bh->b_count); | |
286 | spin_unlock(&journal->j_list_lock); | |
287 | jbd_unlock_bh_state(bh); | |
288 | wait_on_buffer(bh); | |
289 | /* the journal_head may have gone by now */ | |
290 | BUFFER_TRACE(bh, "brelse"); | |
291 | __brelse(bh); | |
292 | ret = 1; | |
293 | } else if (jh->b_transaction != NULL) { | |
294 | transaction_t *t = jh->b_transaction; | |
295 | tid_t tid = t->t_tid; | |
296 | ||
8e85fb3f | 297 | transaction->t_chp_stats.cs_forced_to_close++; |
470decc6 DK |
298 | spin_unlock(&journal->j_list_lock); |
299 | jbd_unlock_bh_state(bh); | |
f7f4bccb MC |
300 | jbd2_log_start_commit(journal, tid); |
301 | jbd2_log_wait_commit(journal, tid); | |
470decc6 DK |
302 | ret = 1; |
303 | } else if (!buffer_dirty(bh)) { | |
44519faf HK |
304 | ret = 1; |
305 | if (unlikely(buffer_write_io_error(bh))) | |
306 | ret = -EIO; | |
470decc6 DK |
307 | J_ASSERT_JH(jh, !buffer_jbddirty(bh)); |
308 | BUFFER_TRACE(bh, "remove from checkpoint"); | |
f7f4bccb | 309 | __jbd2_journal_remove_checkpoint(jh); |
470decc6 DK |
310 | spin_unlock(&journal->j_list_lock); |
311 | jbd_unlock_bh_state(bh); | |
f7f4bccb | 312 | jbd2_journal_remove_journal_head(bh); |
470decc6 | 313 | __brelse(bh); |
470decc6 DK |
314 | } else { |
315 | /* | |
316 | * Important: we are about to write the buffer, and | |
317 | * possibly block, while still holding the journal lock. | |
318 | * We cannot afford to let the transaction logic start | |
319 | * messing around with this buffer before we write it to | |
320 | * disk, as that would break recoverability. | |
321 | */ | |
322 | BUFFER_TRACE(bh, "queue"); | |
323 | get_bh(bh); | |
324 | J_ASSERT_BH(bh, !buffer_jwrite(bh)); | |
325 | set_buffer_jwrite(bh); | |
1a0d3786 | 326 | journal->j_chkpt_bhs[*batch_count] = bh; |
470decc6 DK |
327 | __buffer_relink_io(jh); |
328 | jbd_unlock_bh_state(bh); | |
8e85fb3f | 329 | transaction->t_chp_stats.cs_written++; |
470decc6 | 330 | (*batch_count)++; |
1a0d3786 | 331 | if (*batch_count == JBD2_NR_BATCH) { |
470decc6 | 332 | spin_unlock(&journal->j_list_lock); |
1a0d3786 | 333 | __flush_batch(journal, batch_count); |
470decc6 DK |
334 | ret = 1; |
335 | } | |
336 | } | |
337 | return ret; | |
338 | } | |
339 | ||
340 | /* | |
341 | * Perform an actual checkpoint. We take the first transaction on the | |
342 | * list of transactions to be checkpointed and send all its buffers | |
343 | * to disk. We submit larger chunks of data at once. | |
344 | * | |
345 | * The journal should be locked before calling this function. | |
44519faf | 346 | * Called with j_checkpoint_mutex held. |
470decc6 | 347 | */ |
f7f4bccb | 348 | int jbd2_log_do_checkpoint(journal_t *journal) |
470decc6 DK |
349 | { |
350 | transaction_t *transaction; | |
351 | tid_t this_tid; | |
352 | int result; | |
353 | ||
354 | jbd_debug(1, "Start checkpoint\n"); | |
355 | ||
356 | /* | |
357 | * First thing: if there are any transactions in the log which | |
358 | * don't need checkpointing, just eliminate them from the | |
359 | * journal straight away. | |
360 | */ | |
f7f4bccb | 361 | result = jbd2_cleanup_journal_tail(journal); |
879c5e6b | 362 | trace_jbd2_checkpoint(journal, result); |
470decc6 DK |
363 | jbd_debug(1, "cleanup_journal_tail returned %d\n", result); |
364 | if (result <= 0) | |
365 | return result; | |
366 | ||
367 | /* | |
368 | * OK, we need to start writing disk blocks. Take one transaction | |
369 | * and write it. | |
370 | */ | |
44519faf | 371 | result = 0; |
470decc6 DK |
372 | spin_lock(&journal->j_list_lock); |
373 | if (!journal->j_checkpoint_transactions) | |
374 | goto out; | |
375 | transaction = journal->j_checkpoint_transactions; | |
8e85fb3f JL |
376 | if (transaction->t_chp_stats.cs_chp_time == 0) |
377 | transaction->t_chp_stats.cs_chp_time = jiffies; | |
470decc6 DK |
378 | this_tid = transaction->t_tid; |
379 | restart: | |
380 | /* | |
381 | * If someone cleaned up this transaction while we slept, we're | |
382 | * done (maybe it's a new transaction, but it fell at the same | |
383 | * address). | |
384 | */ | |
385 | if (journal->j_checkpoint_transactions == transaction && | |
386 | transaction->t_tid == this_tid) { | |
387 | int batch_count = 0; | |
470decc6 | 388 | struct journal_head *jh; |
44519faf | 389 | int retry = 0, err; |
470decc6 DK |
390 | |
391 | while (!retry && transaction->t_checkpoint_list) { | |
392 | struct buffer_head *bh; | |
393 | ||
394 | jh = transaction->t_checkpoint_list; | |
395 | bh = jh2bh(jh); | |
396 | if (!jbd_trylock_bh_state(bh)) { | |
397 | jbd_sync_bh(journal, bh); | |
398 | retry = 1; | |
399 | break; | |
400 | } | |
1a0d3786 | 401 | retry = __process_buffer(journal, jh, &batch_count, |
8e85fb3f | 402 | transaction); |
44519faf HK |
403 | if (retry < 0 && !result) |
404 | result = retry; | |
95c354fe NP |
405 | if (!retry && (need_resched() || |
406 | spin_needbreak(&journal->j_list_lock))) { | |
470decc6 DK |
407 | spin_unlock(&journal->j_list_lock); |
408 | retry = 1; | |
409 | break; | |
410 | } | |
411 | } | |
412 | ||
413 | if (batch_count) { | |
414 | if (!retry) { | |
415 | spin_unlock(&journal->j_list_lock); | |
416 | retry = 1; | |
417 | } | |
1a0d3786 | 418 | __flush_batch(journal, &batch_count); |
470decc6 DK |
419 | } |
420 | ||
421 | if (retry) { | |
422 | spin_lock(&journal->j_list_lock); | |
423 | goto restart; | |
424 | } | |
425 | /* | |
426 | * Now we have cleaned up the first transaction's checkpoint | |
427 | * list. Let's clean up the second one | |
428 | */ | |
44519faf HK |
429 | err = __wait_cp_io(journal, transaction); |
430 | if (!result) | |
431 | result = err; | |
470decc6 DK |
432 | } |
433 | out: | |
434 | spin_unlock(&journal->j_list_lock); | |
470decc6 | 435 | if (result < 0) |
44519faf HK |
436 | jbd2_journal_abort(journal, result); |
437 | else | |
438 | result = jbd2_cleanup_journal_tail(journal); | |
439 | ||
440 | return (result < 0) ? result : 0; | |
470decc6 DK |
441 | } |
442 | ||
443 | /* | |
444 | * Check the list of checkpoint transactions for the journal to see if | |
445 | * we have already got rid of any since the last update of the log tail | |
446 | * in the journal superblock. If so, we can instantly roll the | |
447 | * superblock forward to remove those transactions from the log. | |
448 | * | |
449 | * Return <0 on error, 0 on success, 1 if there was nothing to clean up. | |
450 | * | |
451 | * Called with the journal lock held. | |
452 | * | |
453 | * This is the only part of the journaling code which really needs to be | |
454 | * aware of transaction aborts. Checkpointing involves writing to the | |
455 | * main filesystem area rather than to the journal, so it can proceed | |
44519faf HK |
456 | * even in abort state, but we must not update the super block if |
457 | * checkpointing may have failed. Otherwise, we would lose some metadata | |
458 | * buffers which should be written-back to the filesystem. | |
470decc6 DK |
459 | */ |
460 | ||
f7f4bccb | 461 | int jbd2_cleanup_journal_tail(journal_t *journal) |
470decc6 DK |
462 | { |
463 | transaction_t * transaction; | |
464 | tid_t first_tid; | |
465 | unsigned long blocknr, freed; | |
466 | ||
44519faf HK |
467 | if (is_journal_aborted(journal)) |
468 | return 1; | |
469 | ||
470decc6 DK |
470 | /* OK, work out the oldest transaction remaining in the log, and |
471 | * the log block it starts at. | |
472 | * | |
473 | * If the log is now empty, we need to work out which is the | |
474 | * next transaction ID we will write, and where it will | |
475 | * start. */ | |
476 | ||
477 | spin_lock(&journal->j_state_lock); | |
478 | spin_lock(&journal->j_list_lock); | |
479 | transaction = journal->j_checkpoint_transactions; | |
480 | if (transaction) { | |
481 | first_tid = transaction->t_tid; | |
482 | blocknr = transaction->t_log_start; | |
483 | } else if ((transaction = journal->j_committing_transaction) != NULL) { | |
484 | first_tid = transaction->t_tid; | |
485 | blocknr = transaction->t_log_start; | |
486 | } else if ((transaction = journal->j_running_transaction) != NULL) { | |
487 | first_tid = transaction->t_tid; | |
488 | blocknr = journal->j_head; | |
489 | } else { | |
490 | first_tid = journal->j_transaction_sequence; | |
491 | blocknr = journal->j_head; | |
492 | } | |
493 | spin_unlock(&journal->j_list_lock); | |
494 | J_ASSERT(blocknr != 0); | |
495 | ||
496 | /* If the oldest pinned transaction is at the tail of the log | |
497 | already then there's not much we can do right now. */ | |
498 | if (journal->j_tail_sequence == first_tid) { | |
499 | spin_unlock(&journal->j_state_lock); | |
500 | return 1; | |
501 | } | |
502 | ||
503 | /* OK, update the superblock to recover the freed space. | |
504 | * Physical blocks come first: have we wrapped beyond the end of | |
505 | * the log? */ | |
506 | freed = blocknr - journal->j_tail; | |
507 | if (blocknr < journal->j_tail) | |
508 | freed = freed + journal->j_last - journal->j_first; | |
509 | ||
71f2be21 | 510 | trace_jbd2_cleanup_journal_tail(journal, first_tid, blocknr, freed); |
470decc6 DK |
511 | jbd_debug(1, |
512 | "Cleaning journal tail from %d to %d (offset %lu), " | |
513 | "freeing %lu\n", | |
514 | journal->j_tail_sequence, first_tid, blocknr, freed); | |
515 | ||
516 | journal->j_free += freed; | |
517 | journal->j_tail_sequence = first_tid; | |
518 | journal->j_tail = blocknr; | |
519 | spin_unlock(&journal->j_state_lock); | |
cc3e1bea TT |
520 | |
521 | /* | |
522 | * If there is an external journal, we need to make sure that | |
523 | * any data blocks that were recently written out --- perhaps | |
524 | * by jbd2_log_do_checkpoint() --- are flushed out before we | |
525 | * drop the transactions from the external journal. It's | |
526 | * unlikely this will be necessary, especially with a | |
527 | * appropriately sized journal, but we need this to guarantee | |
528 | * correctness. Fortunately jbd2_cleanup_journal_tail() | |
529 | * doesn't get called all that often. | |
530 | */ | |
531 | if ((journal->j_fs_dev != journal->j_dev) && | |
532 | (journal->j_flags & JBD2_BARRIER)) | |
fbd9b09a DM |
533 | blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL, |
534 | BLKDEV_IFL_WAIT); | |
f7f4bccb MC |
535 | if (!(journal->j_flags & JBD2_ABORT)) |
536 | jbd2_journal_update_superblock(journal, 1); | |
470decc6 DK |
537 | return 0; |
538 | } | |
539 | ||
540 | ||
541 | /* Checkpoint list management */ | |
542 | ||
543 | /* | |
544 | * journal_clean_one_cp_list | |
545 | * | |
546 | * Find all the written-back checkpoint buffers in the given list and release them. | |
547 | * | |
548 | * Called with the journal locked. | |
549 | * Called with j_list_lock held. | |
550 | * Returns number of bufers reaped (for debug) | |
551 | */ | |
552 | ||
553 | static int journal_clean_one_cp_list(struct journal_head *jh, int *released) | |
554 | { | |
555 | struct journal_head *last_jh; | |
556 | struct journal_head *next_jh = jh; | |
557 | int ret, freed = 0; | |
558 | ||
559 | *released = 0; | |
560 | if (!jh) | |
561 | return 0; | |
562 | ||
563 | last_jh = jh->b_cpprev; | |
564 | do { | |
565 | jh = next_jh; | |
566 | next_jh = jh->b_cpnext; | |
567 | /* Use trylock because of the ranking */ | |
568 | if (jbd_trylock_bh_state(jh2bh(jh))) { | |
569 | ret = __try_to_free_cp_buf(jh); | |
570 | if (ret) { | |
571 | freed++; | |
572 | if (ret == 2) { | |
573 | *released = 1; | |
574 | return freed; | |
575 | } | |
576 | } | |
577 | } | |
578 | /* | |
579 | * This function only frees up some memory | |
580 | * if possible so we dont have an obligation | |
581 | * to finish processing. Bail out if preemption | |
582 | * requested: | |
583 | */ | |
584 | if (need_resched()) | |
585 | return freed; | |
586 | } while (jh != last_jh); | |
587 | ||
588 | return freed; | |
589 | } | |
590 | ||
591 | /* | |
592 | * journal_clean_checkpoint_list | |
593 | * | |
594 | * Find all the written-back checkpoint buffers in the journal and release them. | |
595 | * | |
596 | * Called with the journal locked. | |
597 | * Called with j_list_lock held. | |
598 | * Returns number of buffers reaped (for debug) | |
599 | */ | |
600 | ||
f7f4bccb | 601 | int __jbd2_journal_clean_checkpoint_list(journal_t *journal) |
470decc6 DK |
602 | { |
603 | transaction_t *transaction, *last_transaction, *next_transaction; | |
604 | int ret = 0; | |
605 | int released; | |
606 | ||
607 | transaction = journal->j_checkpoint_transactions; | |
608 | if (!transaction) | |
609 | goto out; | |
610 | ||
611 | last_transaction = transaction->t_cpprev; | |
612 | next_transaction = transaction; | |
613 | do { | |
614 | transaction = next_transaction; | |
615 | next_transaction = transaction->t_cpnext; | |
616 | ret += journal_clean_one_cp_list(transaction-> | |
617 | t_checkpoint_list, &released); | |
618 | /* | |
619 | * This function only frees up some memory if possible so we | |
620 | * dont have an obligation to finish processing. Bail out if | |
621 | * preemption requested: | |
622 | */ | |
623 | if (need_resched()) | |
624 | goto out; | |
625 | if (released) | |
626 | continue; | |
627 | /* | |
628 | * It is essential that we are as careful as in the case of | |
629 | * t_checkpoint_list with removing the buffer from the list as | |
630 | * we can possibly see not yet submitted buffers on io_list | |
631 | */ | |
632 | ret += journal_clean_one_cp_list(transaction-> | |
633 | t_checkpoint_io_list, &released); | |
634 | if (need_resched()) | |
635 | goto out; | |
636 | } while (transaction != last_transaction); | |
637 | out: | |
638 | return ret; | |
639 | } | |
640 | ||
641 | /* | |
642 | * journal_remove_checkpoint: called after a buffer has been committed | |
643 | * to disk (either by being write-back flushed to disk, or being | |
644 | * committed to the log). | |
645 | * | |
646 | * We cannot safely clean a transaction out of the log until all of the | |
647 | * buffer updates committed in that transaction have safely been stored | |
648 | * elsewhere on disk. To achieve this, all of the buffers in a | |
649 | * transaction need to be maintained on the transaction's checkpoint | |
650 | * lists until they have been rewritten, at which point this function is | |
651 | * called to remove the buffer from the existing transaction's | |
652 | * checkpoint lists. | |
653 | * | |
654 | * The function returns 1 if it frees the transaction, 0 otherwise. | |
655 | * | |
656 | * This function is called with the journal locked. | |
657 | * This function is called with j_list_lock held. | |
658 | * This function is called with jbd_lock_bh_state(jh2bh(jh)) | |
659 | */ | |
660 | ||
f7f4bccb | 661 | int __jbd2_journal_remove_checkpoint(struct journal_head *jh) |
470decc6 | 662 | { |
bf699327 | 663 | struct transaction_chp_stats_s *stats; |
470decc6 DK |
664 | transaction_t *transaction; |
665 | journal_t *journal; | |
666 | int ret = 0; | |
667 | ||
668 | JBUFFER_TRACE(jh, "entry"); | |
669 | ||
670 | if ((transaction = jh->b_cp_transaction) == NULL) { | |
671 | JBUFFER_TRACE(jh, "not on transaction"); | |
672 | goto out; | |
673 | } | |
674 | journal = transaction->t_journal; | |
675 | ||
676 | __buffer_unlink(jh); | |
677 | jh->b_cp_transaction = NULL; | |
678 | ||
679 | if (transaction->t_checkpoint_list != NULL || | |
680 | transaction->t_checkpoint_io_list != NULL) | |
681 | goto out; | |
682 | JBUFFER_TRACE(jh, "transaction has no more buffers"); | |
683 | ||
684 | /* | |
685 | * There is one special case to worry about: if we have just pulled the | |
f5a7a6b0 JK |
686 | * buffer off a running or committing transaction's checkpoing list, |
687 | * then even if the checkpoint list is empty, the transaction obviously | |
688 | * cannot be dropped! | |
470decc6 | 689 | * |
f5a7a6b0 | 690 | * The locking here around t_state is a bit sleazy. |
f7f4bccb | 691 | * See the comment at the end of jbd2_journal_commit_transaction(). |
470decc6 | 692 | */ |
f5a7a6b0 JK |
693 | if (transaction->t_state != T_FINISHED) { |
694 | JBUFFER_TRACE(jh, "belongs to running/committing transaction"); | |
470decc6 DK |
695 | goto out; |
696 | } | |
697 | ||
698 | /* OK, that was the last buffer for the transaction: we can now | |
699 | safely remove this transaction from the log */ | |
bf699327 TT |
700 | stats = &transaction->t_chp_stats; |
701 | if (stats->cs_chp_time) | |
702 | stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time, | |
703 | jiffies); | |
704 | trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev, | |
705 | transaction->t_tid, stats); | |
470decc6 | 706 | |
f7f4bccb | 707 | __jbd2_journal_drop_transaction(journal, transaction); |
fb68407b | 708 | kfree(transaction); |
470decc6 DK |
709 | |
710 | /* Just in case anybody was waiting for more transactions to be | |
711 | checkpointed... */ | |
712 | wake_up(&journal->j_wait_logspace); | |
713 | ret = 1; | |
714 | out: | |
715 | JBUFFER_TRACE(jh, "exit"); | |
716 | return ret; | |
717 | } | |
718 | ||
719 | /* | |
720 | * journal_insert_checkpoint: put a committed buffer onto a checkpoint | |
721 | * list so that we know when it is safe to clean the transaction out of | |
722 | * the log. | |
723 | * | |
724 | * Called with the journal locked. | |
725 | * Called with j_list_lock held. | |
726 | */ | |
f7f4bccb | 727 | void __jbd2_journal_insert_checkpoint(struct journal_head *jh, |
470decc6 DK |
728 | transaction_t *transaction) |
729 | { | |
730 | JBUFFER_TRACE(jh, "entry"); | |
731 | J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh))); | |
732 | J_ASSERT_JH(jh, jh->b_cp_transaction == NULL); | |
733 | ||
734 | jh->b_cp_transaction = transaction; | |
735 | ||
736 | if (!transaction->t_checkpoint_list) { | |
737 | jh->b_cpnext = jh->b_cpprev = jh; | |
738 | } else { | |
739 | jh->b_cpnext = transaction->t_checkpoint_list; | |
740 | jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev; | |
741 | jh->b_cpprev->b_cpnext = jh; | |
742 | jh->b_cpnext->b_cpprev = jh; | |
743 | } | |
744 | transaction->t_checkpoint_list = jh; | |
745 | } | |
746 | ||
747 | /* | |
748 | * We've finished with this transaction structure: adios... | |
749 | * | |
750 | * The transaction must have no links except for the checkpoint by this | |
751 | * point. | |
752 | * | |
753 | * Called with the journal locked. | |
754 | * Called with j_list_lock held. | |
755 | */ | |
756 | ||
f7f4bccb | 757 | void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
758 | { |
759 | assert_spin_locked(&journal->j_list_lock); | |
760 | if (transaction->t_cpnext) { | |
761 | transaction->t_cpnext->t_cpprev = transaction->t_cpprev; | |
762 | transaction->t_cpprev->t_cpnext = transaction->t_cpnext; | |
763 | if (journal->j_checkpoint_transactions == transaction) | |
764 | journal->j_checkpoint_transactions = | |
765 | transaction->t_cpnext; | |
766 | if (journal->j_checkpoint_transactions == transaction) | |
767 | journal->j_checkpoint_transactions = NULL; | |
768 | } | |
769 | ||
770 | J_ASSERT(transaction->t_state == T_FINISHED); | |
771 | J_ASSERT(transaction->t_buffers == NULL); | |
470decc6 DK |
772 | J_ASSERT(transaction->t_forget == NULL); |
773 | J_ASSERT(transaction->t_iobuf_list == NULL); | |
774 | J_ASSERT(transaction->t_shadow_list == NULL); | |
775 | J_ASSERT(transaction->t_log_list == NULL); | |
776 | J_ASSERT(transaction->t_checkpoint_list == NULL); | |
777 | J_ASSERT(transaction->t_checkpoint_io_list == NULL); | |
a51dca9c | 778 | J_ASSERT(atomic_read(&transaction->t_updates) == 0); |
470decc6 DK |
779 | J_ASSERT(journal->j_committing_transaction != transaction); |
780 | J_ASSERT(journal->j_running_transaction != transaction); | |
781 | ||
782 | jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid); | |
470decc6 | 783 | } |