Commit | Line | Data |
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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)) { | |
de1b7941 JK |
100 | /* |
101 | * Get our reference so that bh cannot be freed before | |
102 | * we unlock it | |
103 | */ | |
104 | get_bh(bh); | |
470decc6 | 105 | JBUFFER_TRACE(jh, "remove from checkpoint list"); |
f7f4bccb | 106 | ret = __jbd2_journal_remove_checkpoint(jh) + 1; |
470decc6 | 107 | jbd_unlock_bh_state(bh); |
470decc6 DK |
108 | BUFFER_TRACE(bh, "release"); |
109 | __brelse(bh); | |
110 | } else { | |
111 | jbd_unlock_bh_state(bh); | |
112 | } | |
113 | return ret; | |
114 | } | |
115 | ||
116 | /* | |
f7f4bccb | 117 | * __jbd2_log_wait_for_space: wait until there is space in the journal. |
470decc6 DK |
118 | * |
119 | * Called under j-state_lock *only*. It will be unlocked if we have to wait | |
120 | * for a checkpoint to free up some space in the log. | |
121 | */ | |
f7f4bccb | 122 | void __jbd2_log_wait_for_space(journal_t *journal) |
470decc6 | 123 | { |
8c3f25d8 | 124 | int nblocks, space_left; |
a931da6a | 125 | /* assert_spin_locked(&journal->j_state_lock); */ |
470decc6 DK |
126 | |
127 | nblocks = jbd_space_needed(journal); | |
f7f4bccb MC |
128 | while (__jbd2_log_space_left(journal) < nblocks) { |
129 | if (journal->j_flags & JBD2_ABORT) | |
470decc6 | 130 | return; |
a931da6a | 131 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
132 | mutex_lock(&journal->j_checkpoint_mutex); |
133 | ||
134 | /* | |
135 | * Test again, another process may have checkpointed while we | |
23f8b79e | 136 | * were waiting for the checkpoint lock. If there are no |
8c3f25d8 TT |
137 | * transactions ready to be checkpointed, try to recover |
138 | * journal space by calling cleanup_journal_tail(), and if | |
139 | * that doesn't work, by waiting for the currently committing | |
140 | * transaction to complete. If there is absolutely no way | |
141 | * to make progress, this is either a BUG or corrupted | |
142 | * filesystem, so abort the journal and leave a stack | |
143 | * trace for forensic evidence. | |
470decc6 | 144 | */ |
a931da6a | 145 | write_lock(&journal->j_state_lock); |
23f8b79e | 146 | spin_lock(&journal->j_list_lock); |
470decc6 | 147 | nblocks = jbd_space_needed(journal); |
8c3f25d8 TT |
148 | space_left = __jbd2_log_space_left(journal); |
149 | if (space_left < nblocks) { | |
23f8b79e | 150 | int chkpt = journal->j_checkpoint_transactions != NULL; |
8c3f25d8 | 151 | tid_t tid = 0; |
23f8b79e | 152 | |
8c3f25d8 TT |
153 | if (journal->j_committing_transaction) |
154 | tid = journal->j_committing_transaction->t_tid; | |
23f8b79e | 155 | spin_unlock(&journal->j_list_lock); |
a931da6a | 156 | write_unlock(&journal->j_state_lock); |
23f8b79e DG |
157 | if (chkpt) { |
158 | jbd2_log_do_checkpoint(journal); | |
8c3f25d8 TT |
159 | } else if (jbd2_cleanup_journal_tail(journal) == 0) { |
160 | /* We were able to recover space; yay! */ | |
161 | ; | |
162 | } else if (tid) { | |
163 | jbd2_log_wait_commit(journal, tid); | |
23f8b79e | 164 | } else { |
8c3f25d8 TT |
165 | printk(KERN_ERR "%s: needed %d blocks and " |
166 | "only had %d space available\n", | |
167 | __func__, nblocks, space_left); | |
168 | printk(KERN_ERR "%s: no way to get more " | |
169 | "journal space in %s\n", __func__, | |
170 | journal->j_devname); | |
171 | WARN_ON(1); | |
23f8b79e DG |
172 | jbd2_journal_abort(journal, 0); |
173 | } | |
a931da6a | 174 | write_lock(&journal->j_state_lock); |
23f8b79e DG |
175 | } else { |
176 | spin_unlock(&journal->j_list_lock); | |
470decc6 DK |
177 | } |
178 | mutex_unlock(&journal->j_checkpoint_mutex); | |
179 | } | |
180 | } | |
181 | ||
182 | /* | |
183 | * We were unable to perform jbd_trylock_bh_state() inside j_list_lock. | |
184 | * The caller must restart a list walk. Wait for someone else to run | |
185 | * jbd_unlock_bh_state(). | |
186 | */ | |
187 | static void jbd_sync_bh(journal_t *journal, struct buffer_head *bh) | |
188 | __releases(journal->j_list_lock) | |
189 | { | |
190 | get_bh(bh); | |
191 | spin_unlock(&journal->j_list_lock); | |
192 | jbd_lock_bh_state(bh); | |
193 | jbd_unlock_bh_state(bh); | |
194 | put_bh(bh); | |
195 | } | |
196 | ||
197 | /* | |
198 | * Clean up transaction's list of buffers submitted for io. | |
199 | * We wait for any pending IO to complete and remove any clean | |
200 | * buffers. Note that we take the buffers in the opposite ordering | |
201 | * from the one in which they were submitted for IO. | |
202 | * | |
44519faf HK |
203 | * Return 0 on success, and return <0 if some buffers have failed |
204 | * to be written out. | |
205 | * | |
470decc6 DK |
206 | * Called with j_list_lock held. |
207 | */ | |
44519faf | 208 | static int __wait_cp_io(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
209 | { |
210 | struct journal_head *jh; | |
211 | struct buffer_head *bh; | |
212 | tid_t this_tid; | |
213 | int released = 0; | |
44519faf | 214 | int ret = 0; |
470decc6 DK |
215 | |
216 | this_tid = transaction->t_tid; | |
217 | restart: | |
218 | /* Did somebody clean up the transaction in the meanwhile? */ | |
219 | if (journal->j_checkpoint_transactions != transaction || | |
220 | transaction->t_tid != this_tid) | |
44519faf | 221 | return ret; |
470decc6 DK |
222 | while (!released && transaction->t_checkpoint_io_list) { |
223 | jh = transaction->t_checkpoint_io_list; | |
224 | bh = jh2bh(jh); | |
225 | if (!jbd_trylock_bh_state(bh)) { | |
226 | jbd_sync_bh(journal, bh); | |
227 | spin_lock(&journal->j_list_lock); | |
228 | goto restart; | |
229 | } | |
de1b7941 | 230 | get_bh(bh); |
470decc6 | 231 | if (buffer_locked(bh)) { |
470decc6 DK |
232 | spin_unlock(&journal->j_list_lock); |
233 | jbd_unlock_bh_state(bh); | |
234 | wait_on_buffer(bh); | |
235 | /* the journal_head may have gone by now */ | |
236 | BUFFER_TRACE(bh, "brelse"); | |
237 | __brelse(bh); | |
238 | spin_lock(&journal->j_list_lock); | |
239 | goto restart; | |
240 | } | |
44519faf HK |
241 | if (unlikely(buffer_write_io_error(bh))) |
242 | ret = -EIO; | |
243 | ||
470decc6 DK |
244 | /* |
245 | * Now in whatever state the buffer currently is, we know that | |
246 | * it has been written out and so we can drop it from the list | |
247 | */ | |
f7f4bccb | 248 | released = __jbd2_journal_remove_checkpoint(jh); |
470decc6 | 249 | jbd_unlock_bh_state(bh); |
470decc6 DK |
250 | __brelse(bh); |
251 | } | |
44519faf HK |
252 | |
253 | return ret; | |
470decc6 DK |
254 | } |
255 | ||
470decc6 | 256 | static void |
1a0d3786 | 257 | __flush_batch(journal_t *journal, int *batch_count) |
470decc6 DK |
258 | { |
259 | int i; | |
d3ad8434 | 260 | struct blk_plug plug; |
470decc6 | 261 | |
d3ad8434 | 262 | blk_start_plug(&plug); |
9cb569d6 | 263 | for (i = 0; i < *batch_count; i++) |
d3ad8434 TM |
264 | write_dirty_buffer(journal->j_chkpt_bhs[i], WRITE_SYNC); |
265 | blk_finish_plug(&plug); | |
9cb569d6 | 266 | |
470decc6 | 267 | for (i = 0; i < *batch_count; i++) { |
1a0d3786 | 268 | struct buffer_head *bh = journal->j_chkpt_bhs[i]; |
470decc6 DK |
269 | BUFFER_TRACE(bh, "brelse"); |
270 | __brelse(bh); | |
271 | } | |
272 | *batch_count = 0; | |
273 | } | |
274 | ||
275 | /* | |
276 | * Try to flush one buffer from the checkpoint list to disk. | |
277 | * | |
278 | * Return 1 if something happened which requires us to abort the current | |
44519faf HK |
279 | * scan of the checkpoint list. Return <0 if the buffer has failed to |
280 | * be written out. | |
470decc6 DK |
281 | * |
282 | * Called with j_list_lock held and drops it if 1 is returned | |
283 | * Called under jbd_lock_bh_state(jh2bh(jh)), and drops it | |
284 | */ | |
285 | static int __process_buffer(journal_t *journal, struct journal_head *jh, | |
1a0d3786 | 286 | int *batch_count, transaction_t *transaction) |
470decc6 DK |
287 | { |
288 | struct buffer_head *bh = jh2bh(jh); | |
289 | int ret = 0; | |
290 | ||
291 | if (buffer_locked(bh)) { | |
de1b7941 | 292 | get_bh(bh); |
470decc6 DK |
293 | spin_unlock(&journal->j_list_lock); |
294 | jbd_unlock_bh_state(bh); | |
295 | wait_on_buffer(bh); | |
296 | /* the journal_head may have gone by now */ | |
297 | BUFFER_TRACE(bh, "brelse"); | |
298 | __brelse(bh); | |
299 | ret = 1; | |
300 | } else if (jh->b_transaction != NULL) { | |
301 | transaction_t *t = jh->b_transaction; | |
302 | tid_t tid = t->t_tid; | |
303 | ||
8e85fb3f | 304 | transaction->t_chp_stats.cs_forced_to_close++; |
470decc6 DK |
305 | spin_unlock(&journal->j_list_lock); |
306 | jbd_unlock_bh_state(bh); | |
5c2178e7 TT |
307 | if (unlikely(journal->j_flags & JBD2_UNMOUNT)) |
308 | /* | |
309 | * The journal thread is dead; so starting and | |
310 | * waiting for a commit to finish will cause | |
311 | * us to wait for a _very_ long time. | |
312 | */ | |
313 | printk(KERN_ERR "JBD2: %s: " | |
314 | "Waiting for Godot: block %llu\n", | |
315 | journal->j_devname, | |
316 | (unsigned long long) bh->b_blocknr); | |
f7f4bccb MC |
317 | jbd2_log_start_commit(journal, tid); |
318 | jbd2_log_wait_commit(journal, tid); | |
470decc6 DK |
319 | ret = 1; |
320 | } else if (!buffer_dirty(bh)) { | |
44519faf HK |
321 | ret = 1; |
322 | if (unlikely(buffer_write_io_error(bh))) | |
323 | ret = -EIO; | |
de1b7941 | 324 | get_bh(bh); |
470decc6 DK |
325 | J_ASSERT_JH(jh, !buffer_jbddirty(bh)); |
326 | BUFFER_TRACE(bh, "remove from checkpoint"); | |
f7f4bccb | 327 | __jbd2_journal_remove_checkpoint(jh); |
470decc6 DK |
328 | spin_unlock(&journal->j_list_lock); |
329 | jbd_unlock_bh_state(bh); | |
470decc6 | 330 | __brelse(bh); |
470decc6 DK |
331 | } else { |
332 | /* | |
333 | * Important: we are about to write the buffer, and | |
334 | * possibly block, while still holding the journal lock. | |
335 | * We cannot afford to let the transaction logic start | |
336 | * messing around with this buffer before we write it to | |
337 | * disk, as that would break recoverability. | |
338 | */ | |
339 | BUFFER_TRACE(bh, "queue"); | |
340 | get_bh(bh); | |
341 | J_ASSERT_BH(bh, !buffer_jwrite(bh)); | |
1a0d3786 | 342 | journal->j_chkpt_bhs[*batch_count] = bh; |
470decc6 DK |
343 | __buffer_relink_io(jh); |
344 | jbd_unlock_bh_state(bh); | |
8e85fb3f | 345 | transaction->t_chp_stats.cs_written++; |
470decc6 | 346 | (*batch_count)++; |
1a0d3786 | 347 | if (*batch_count == JBD2_NR_BATCH) { |
470decc6 | 348 | spin_unlock(&journal->j_list_lock); |
1a0d3786 | 349 | __flush_batch(journal, batch_count); |
470decc6 DK |
350 | ret = 1; |
351 | } | |
352 | } | |
353 | return ret; | |
354 | } | |
355 | ||
356 | /* | |
357 | * Perform an actual checkpoint. We take the first transaction on the | |
358 | * list of transactions to be checkpointed and send all its buffers | |
359 | * to disk. We submit larger chunks of data at once. | |
360 | * | |
361 | * The journal should be locked before calling this function. | |
44519faf | 362 | * Called with j_checkpoint_mutex held. |
470decc6 | 363 | */ |
f7f4bccb | 364 | int jbd2_log_do_checkpoint(journal_t *journal) |
470decc6 DK |
365 | { |
366 | transaction_t *transaction; | |
367 | tid_t this_tid; | |
368 | int result; | |
369 | ||
370 | jbd_debug(1, "Start checkpoint\n"); | |
371 | ||
372 | /* | |
373 | * First thing: if there are any transactions in the log which | |
374 | * don't need checkpointing, just eliminate them from the | |
375 | * journal straight away. | |
376 | */ | |
f7f4bccb | 377 | result = jbd2_cleanup_journal_tail(journal); |
879c5e6b | 378 | trace_jbd2_checkpoint(journal, result); |
470decc6 DK |
379 | jbd_debug(1, "cleanup_journal_tail returned %d\n", result); |
380 | if (result <= 0) | |
381 | return result; | |
382 | ||
383 | /* | |
384 | * OK, we need to start writing disk blocks. Take one transaction | |
385 | * and write it. | |
386 | */ | |
44519faf | 387 | result = 0; |
470decc6 DK |
388 | spin_lock(&journal->j_list_lock); |
389 | if (!journal->j_checkpoint_transactions) | |
390 | goto out; | |
391 | transaction = journal->j_checkpoint_transactions; | |
8e85fb3f JL |
392 | if (transaction->t_chp_stats.cs_chp_time == 0) |
393 | transaction->t_chp_stats.cs_chp_time = jiffies; | |
470decc6 DK |
394 | this_tid = transaction->t_tid; |
395 | restart: | |
396 | /* | |
397 | * If someone cleaned up this transaction while we slept, we're | |
398 | * done (maybe it's a new transaction, but it fell at the same | |
399 | * address). | |
400 | */ | |
401 | if (journal->j_checkpoint_transactions == transaction && | |
402 | transaction->t_tid == this_tid) { | |
403 | int batch_count = 0; | |
470decc6 | 404 | struct journal_head *jh; |
44519faf | 405 | int retry = 0, err; |
470decc6 DK |
406 | |
407 | while (!retry && transaction->t_checkpoint_list) { | |
408 | struct buffer_head *bh; | |
409 | ||
410 | jh = transaction->t_checkpoint_list; | |
411 | bh = jh2bh(jh); | |
412 | if (!jbd_trylock_bh_state(bh)) { | |
413 | jbd_sync_bh(journal, bh); | |
414 | retry = 1; | |
415 | break; | |
416 | } | |
1a0d3786 | 417 | retry = __process_buffer(journal, jh, &batch_count, |
8e85fb3f | 418 | transaction); |
44519faf HK |
419 | if (retry < 0 && !result) |
420 | result = retry; | |
95c354fe NP |
421 | if (!retry && (need_resched() || |
422 | spin_needbreak(&journal->j_list_lock))) { | |
470decc6 DK |
423 | spin_unlock(&journal->j_list_lock); |
424 | retry = 1; | |
425 | break; | |
426 | } | |
427 | } | |
428 | ||
429 | if (batch_count) { | |
430 | if (!retry) { | |
431 | spin_unlock(&journal->j_list_lock); | |
432 | retry = 1; | |
433 | } | |
1a0d3786 | 434 | __flush_batch(journal, &batch_count); |
470decc6 DK |
435 | } |
436 | ||
437 | if (retry) { | |
438 | spin_lock(&journal->j_list_lock); | |
439 | goto restart; | |
440 | } | |
441 | /* | |
442 | * Now we have cleaned up the first transaction's checkpoint | |
443 | * list. Let's clean up the second one | |
444 | */ | |
44519faf HK |
445 | err = __wait_cp_io(journal, transaction); |
446 | if (!result) | |
447 | result = err; | |
470decc6 DK |
448 | } |
449 | out: | |
450 | spin_unlock(&journal->j_list_lock); | |
470decc6 | 451 | if (result < 0) |
44519faf HK |
452 | jbd2_journal_abort(journal, result); |
453 | else | |
454 | result = jbd2_cleanup_journal_tail(journal); | |
455 | ||
456 | return (result < 0) ? result : 0; | |
470decc6 DK |
457 | } |
458 | ||
459 | /* | |
460 | * Check the list of checkpoint transactions for the journal to see if | |
461 | * we have already got rid of any since the last update of the log tail | |
462 | * in the journal superblock. If so, we can instantly roll the | |
463 | * superblock forward to remove those transactions from the log. | |
464 | * | |
465 | * Return <0 on error, 0 on success, 1 if there was nothing to clean up. | |
466 | * | |
467 | * Called with the journal lock held. | |
468 | * | |
469 | * This is the only part of the journaling code which really needs to be | |
470 | * aware of transaction aborts. Checkpointing involves writing to the | |
471 | * main filesystem area rather than to the journal, so it can proceed | |
44519faf HK |
472 | * even in abort state, but we must not update the super block if |
473 | * checkpointing may have failed. Otherwise, we would lose some metadata | |
474 | * buffers which should be written-back to the filesystem. | |
470decc6 DK |
475 | */ |
476 | ||
f7f4bccb | 477 | int jbd2_cleanup_journal_tail(journal_t *journal) |
470decc6 | 478 | { |
470decc6 | 479 | tid_t first_tid; |
79feb521 | 480 | unsigned long blocknr; |
470decc6 | 481 | |
44519faf HK |
482 | if (is_journal_aborted(journal)) |
483 | return 1; | |
484 | ||
79feb521 | 485 | if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr)) |
470decc6 | 486 | return 1; |
79feb521 | 487 | J_ASSERT(blocknr != 0); |
cc3e1bea TT |
488 | |
489 | /* | |
79feb521 JK |
490 | * We need to make sure that any blocks that were recently written out |
491 | * --- perhaps by jbd2_log_do_checkpoint() --- are flushed out before | |
492 | * we drop the transactions from the journal. It's unlikely this will | |
493 | * be necessary, especially with an appropriately sized journal, but we | |
494 | * need this to guarantee correctness. Fortunately | |
495 | * jbd2_cleanup_journal_tail() doesn't get called all that often. | |
cc3e1bea | 496 | */ |
79feb521 | 497 | if (journal->j_flags & JBD2_BARRIER) |
dd3932ed | 498 | blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL); |
79feb521 JK |
499 | |
500 | __jbd2_update_log_tail(journal, first_tid, blocknr); | |
470decc6 DK |
501 | return 0; |
502 | } | |
503 | ||
504 | ||
505 | /* Checkpoint list management */ | |
506 | ||
507 | /* | |
508 | * journal_clean_one_cp_list | |
509 | * | |
de1b7941 JK |
510 | * Find all the written-back checkpoint buffers in the given list and |
511 | * release them. | |
470decc6 DK |
512 | * |
513 | * Called with the journal locked. | |
514 | * Called with j_list_lock held. | |
90802ed9 | 515 | * Returns number of buffers reaped (for debug) |
470decc6 DK |
516 | */ |
517 | ||
518 | static int journal_clean_one_cp_list(struct journal_head *jh, int *released) | |
519 | { | |
520 | struct journal_head *last_jh; | |
521 | struct journal_head *next_jh = jh; | |
522 | int ret, freed = 0; | |
523 | ||
524 | *released = 0; | |
525 | if (!jh) | |
526 | return 0; | |
527 | ||
528 | last_jh = jh->b_cpprev; | |
529 | do { | |
530 | jh = next_jh; | |
531 | next_jh = jh->b_cpnext; | |
532 | /* Use trylock because of the ranking */ | |
533 | if (jbd_trylock_bh_state(jh2bh(jh))) { | |
534 | ret = __try_to_free_cp_buf(jh); | |
535 | if (ret) { | |
536 | freed++; | |
537 | if (ret == 2) { | |
538 | *released = 1; | |
539 | return freed; | |
540 | } | |
541 | } | |
542 | } | |
543 | /* | |
544 | * This function only frees up some memory | |
545 | * if possible so we dont have an obligation | |
546 | * to finish processing. Bail out if preemption | |
547 | * requested: | |
548 | */ | |
549 | if (need_resched()) | |
550 | return freed; | |
551 | } while (jh != last_jh); | |
552 | ||
553 | return freed; | |
554 | } | |
555 | ||
556 | /* | |
557 | * journal_clean_checkpoint_list | |
558 | * | |
559 | * Find all the written-back checkpoint buffers in the journal and release them. | |
560 | * | |
561 | * Called with the journal locked. | |
562 | * Called with j_list_lock held. | |
563 | * Returns number of buffers reaped (for debug) | |
564 | */ | |
565 | ||
f7f4bccb | 566 | int __jbd2_journal_clean_checkpoint_list(journal_t *journal) |
470decc6 DK |
567 | { |
568 | transaction_t *transaction, *last_transaction, *next_transaction; | |
569 | int ret = 0; | |
570 | int released; | |
571 | ||
572 | transaction = journal->j_checkpoint_transactions; | |
573 | if (!transaction) | |
574 | goto out; | |
575 | ||
576 | last_transaction = transaction->t_cpprev; | |
577 | next_transaction = transaction; | |
578 | do { | |
579 | transaction = next_transaction; | |
580 | next_transaction = transaction->t_cpnext; | |
581 | ret += journal_clean_one_cp_list(transaction-> | |
582 | t_checkpoint_list, &released); | |
583 | /* | |
584 | * This function only frees up some memory if possible so we | |
585 | * dont have an obligation to finish processing. Bail out if | |
586 | * preemption requested: | |
587 | */ | |
588 | if (need_resched()) | |
589 | goto out; | |
590 | if (released) | |
591 | continue; | |
592 | /* | |
593 | * It is essential that we are as careful as in the case of | |
594 | * t_checkpoint_list with removing the buffer from the list as | |
595 | * we can possibly see not yet submitted buffers on io_list | |
596 | */ | |
597 | ret += journal_clean_one_cp_list(transaction-> | |
598 | t_checkpoint_io_list, &released); | |
599 | if (need_resched()) | |
600 | goto out; | |
601 | } while (transaction != last_transaction); | |
602 | out: | |
603 | return ret; | |
604 | } | |
605 | ||
606 | /* | |
607 | * journal_remove_checkpoint: called after a buffer has been committed | |
608 | * to disk (either by being write-back flushed to disk, or being | |
609 | * committed to the log). | |
610 | * | |
611 | * We cannot safely clean a transaction out of the log until all of the | |
612 | * buffer updates committed in that transaction have safely been stored | |
613 | * elsewhere on disk. To achieve this, all of the buffers in a | |
614 | * transaction need to be maintained on the transaction's checkpoint | |
615 | * lists until they have been rewritten, at which point this function is | |
616 | * called to remove the buffer from the existing transaction's | |
617 | * checkpoint lists. | |
618 | * | |
619 | * The function returns 1 if it frees the transaction, 0 otherwise. | |
de1b7941 | 620 | * The function can free jh and bh. |
470decc6 | 621 | * |
470decc6 DK |
622 | * This function is called with j_list_lock held. |
623 | * This function is called with jbd_lock_bh_state(jh2bh(jh)) | |
624 | */ | |
625 | ||
f7f4bccb | 626 | int __jbd2_journal_remove_checkpoint(struct journal_head *jh) |
470decc6 | 627 | { |
bf699327 | 628 | struct transaction_chp_stats_s *stats; |
470decc6 DK |
629 | transaction_t *transaction; |
630 | journal_t *journal; | |
631 | int ret = 0; | |
632 | ||
633 | JBUFFER_TRACE(jh, "entry"); | |
634 | ||
635 | if ((transaction = jh->b_cp_transaction) == NULL) { | |
636 | JBUFFER_TRACE(jh, "not on transaction"); | |
637 | goto out; | |
638 | } | |
639 | journal = transaction->t_journal; | |
640 | ||
de1b7941 | 641 | JBUFFER_TRACE(jh, "removing from transaction"); |
470decc6 DK |
642 | __buffer_unlink(jh); |
643 | jh->b_cp_transaction = NULL; | |
de1b7941 | 644 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
645 | |
646 | if (transaction->t_checkpoint_list != NULL || | |
647 | transaction->t_checkpoint_io_list != NULL) | |
648 | goto out; | |
470decc6 DK |
649 | |
650 | /* | |
651 | * There is one special case to worry about: if we have just pulled the | |
f5a7a6b0 JK |
652 | * buffer off a running or committing transaction's checkpoing list, |
653 | * then even if the checkpoint list is empty, the transaction obviously | |
654 | * cannot be dropped! | |
470decc6 | 655 | * |
f5a7a6b0 | 656 | * The locking here around t_state is a bit sleazy. |
f7f4bccb | 657 | * See the comment at the end of jbd2_journal_commit_transaction(). |
470decc6 | 658 | */ |
de1b7941 | 659 | if (transaction->t_state != T_FINISHED) |
470decc6 | 660 | goto out; |
470decc6 DK |
661 | |
662 | /* OK, that was the last buffer for the transaction: we can now | |
663 | safely remove this transaction from the log */ | |
bf699327 TT |
664 | stats = &transaction->t_chp_stats; |
665 | if (stats->cs_chp_time) | |
666 | stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time, | |
667 | jiffies); | |
668 | trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev, | |
669 | transaction->t_tid, stats); | |
470decc6 | 670 | |
f7f4bccb | 671 | __jbd2_journal_drop_transaction(journal, transaction); |
0c2022ec | 672 | jbd2_journal_free_transaction(transaction); |
470decc6 DK |
673 | |
674 | /* Just in case anybody was waiting for more transactions to be | |
675 | checkpointed... */ | |
676 | wake_up(&journal->j_wait_logspace); | |
677 | ret = 1; | |
678 | out: | |
470decc6 DK |
679 | return ret; |
680 | } | |
681 | ||
682 | /* | |
683 | * journal_insert_checkpoint: put a committed buffer onto a checkpoint | |
684 | * list so that we know when it is safe to clean the transaction out of | |
685 | * the log. | |
686 | * | |
687 | * Called with the journal locked. | |
688 | * Called with j_list_lock held. | |
689 | */ | |
f7f4bccb | 690 | void __jbd2_journal_insert_checkpoint(struct journal_head *jh, |
470decc6 DK |
691 | transaction_t *transaction) |
692 | { | |
693 | JBUFFER_TRACE(jh, "entry"); | |
694 | J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh))); | |
695 | J_ASSERT_JH(jh, jh->b_cp_transaction == NULL); | |
696 | ||
de1b7941 JK |
697 | /* Get reference for checkpointing transaction */ |
698 | jbd2_journal_grab_journal_head(jh2bh(jh)); | |
470decc6 DK |
699 | jh->b_cp_transaction = transaction; |
700 | ||
701 | if (!transaction->t_checkpoint_list) { | |
702 | jh->b_cpnext = jh->b_cpprev = jh; | |
703 | } else { | |
704 | jh->b_cpnext = transaction->t_checkpoint_list; | |
705 | jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev; | |
706 | jh->b_cpprev->b_cpnext = jh; | |
707 | jh->b_cpnext->b_cpprev = jh; | |
708 | } | |
709 | transaction->t_checkpoint_list = jh; | |
710 | } | |
711 | ||
712 | /* | |
713 | * We've finished with this transaction structure: adios... | |
714 | * | |
715 | * The transaction must have no links except for the checkpoint by this | |
716 | * point. | |
717 | * | |
718 | * Called with the journal locked. | |
719 | * Called with j_list_lock held. | |
720 | */ | |
721 | ||
f7f4bccb | 722 | void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
723 | { |
724 | assert_spin_locked(&journal->j_list_lock); | |
725 | if (transaction->t_cpnext) { | |
726 | transaction->t_cpnext->t_cpprev = transaction->t_cpprev; | |
727 | transaction->t_cpprev->t_cpnext = transaction->t_cpnext; | |
728 | if (journal->j_checkpoint_transactions == transaction) | |
729 | journal->j_checkpoint_transactions = | |
730 | transaction->t_cpnext; | |
731 | if (journal->j_checkpoint_transactions == transaction) | |
732 | journal->j_checkpoint_transactions = NULL; | |
733 | } | |
734 | ||
735 | J_ASSERT(transaction->t_state == T_FINISHED); | |
736 | J_ASSERT(transaction->t_buffers == NULL); | |
470decc6 DK |
737 | J_ASSERT(transaction->t_forget == NULL); |
738 | J_ASSERT(transaction->t_iobuf_list == NULL); | |
739 | J_ASSERT(transaction->t_shadow_list == NULL); | |
740 | J_ASSERT(transaction->t_log_list == NULL); | |
741 | J_ASSERT(transaction->t_checkpoint_list == NULL); | |
742 | J_ASSERT(transaction->t_checkpoint_io_list == NULL); | |
a51dca9c | 743 | J_ASSERT(atomic_read(&transaction->t_updates) == 0); |
470decc6 DK |
744 | J_ASSERT(journal->j_committing_transaction != transaction); |
745 | J_ASSERT(journal->j_running_transaction != transaction); | |
746 | ||
2201c590 SA |
747 | trace_jbd2_drop_transaction(journal, transaction); |
748 | ||
470decc6 | 749 | jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid); |
470decc6 | 750 | } |