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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 | |
470decc6 DK |
91 | */ |
92 | static int __try_to_free_cp_buf(struct journal_head *jh) | |
93 | { | |
94 | int ret = 0; | |
95 | struct buffer_head *bh = jh2bh(jh); | |
96 | ||
932bb305 | 97 | if (jh->b_transaction == NULL && !buffer_locked(bh) && |
44519faf | 98 | !buffer_dirty(bh) && !buffer_write_io_error(bh)) { |
470decc6 | 99 | JBUFFER_TRACE(jh, "remove from checkpoint list"); |
f7f4bccb | 100 | ret = __jbd2_journal_remove_checkpoint(jh) + 1; |
470decc6 DK |
101 | } |
102 | return ret; | |
103 | } | |
104 | ||
105 | /* | |
f7f4bccb | 106 | * __jbd2_log_wait_for_space: wait until there is space in the journal. |
470decc6 DK |
107 | * |
108 | * Called under j-state_lock *only*. It will be unlocked if we have to wait | |
109 | * for a checkpoint to free up some space in the log. | |
110 | */ | |
f7f4bccb | 111 | void __jbd2_log_wait_for_space(journal_t *journal) |
470decc6 | 112 | { |
8c3f25d8 | 113 | int nblocks, space_left; |
a931da6a | 114 | /* assert_spin_locked(&journal->j_state_lock); */ |
470decc6 | 115 | |
76c39904 JK |
116 | nblocks = jbd2_space_needed(journal); |
117 | while (jbd2_log_space_left(journal) < nblocks) { | |
a931da6a | 118 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
119 | mutex_lock(&journal->j_checkpoint_mutex); |
120 | ||
121 | /* | |
122 | * Test again, another process may have checkpointed while we | |
23f8b79e | 123 | * were waiting for the checkpoint lock. If there are no |
8c3f25d8 TT |
124 | * transactions ready to be checkpointed, try to recover |
125 | * journal space by calling cleanup_journal_tail(), and if | |
126 | * that doesn't work, by waiting for the currently committing | |
127 | * transaction to complete. If there is absolutely no way | |
128 | * to make progress, this is either a BUG or corrupted | |
129 | * filesystem, so abort the journal and leave a stack | |
130 | * trace for forensic evidence. | |
470decc6 | 131 | */ |
a931da6a | 132 | write_lock(&journal->j_state_lock); |
1245799f DM |
133 | if (journal->j_flags & JBD2_ABORT) { |
134 | mutex_unlock(&journal->j_checkpoint_mutex); | |
135 | return; | |
136 | } | |
23f8b79e | 137 | spin_lock(&journal->j_list_lock); |
76c39904 JK |
138 | nblocks = jbd2_space_needed(journal); |
139 | space_left = jbd2_log_space_left(journal); | |
8c3f25d8 | 140 | if (space_left < nblocks) { |
23f8b79e | 141 | int chkpt = journal->j_checkpoint_transactions != NULL; |
8c3f25d8 | 142 | tid_t tid = 0; |
23f8b79e | 143 | |
8c3f25d8 TT |
144 | if (journal->j_committing_transaction) |
145 | tid = journal->j_committing_transaction->t_tid; | |
23f8b79e | 146 | spin_unlock(&journal->j_list_lock); |
a931da6a | 147 | write_unlock(&journal->j_state_lock); |
23f8b79e DG |
148 | if (chkpt) { |
149 | jbd2_log_do_checkpoint(journal); | |
8c3f25d8 TT |
150 | } else if (jbd2_cleanup_journal_tail(journal) == 0) { |
151 | /* We were able to recover space; yay! */ | |
152 | ; | |
153 | } else if (tid) { | |
0ef54180 PG |
154 | /* |
155 | * jbd2_journal_commit_transaction() may want | |
156 | * to take the checkpoint_mutex if JBD2_FLUSHED | |
157 | * is set. So we need to temporarily drop it. | |
158 | */ | |
159 | mutex_unlock(&journal->j_checkpoint_mutex); | |
8c3f25d8 | 160 | jbd2_log_wait_commit(journal, tid); |
0ef54180 PG |
161 | write_lock(&journal->j_state_lock); |
162 | continue; | |
23f8b79e | 163 | } else { |
8c3f25d8 TT |
164 | printk(KERN_ERR "%s: needed %d blocks and " |
165 | "only had %d space available\n", | |
166 | __func__, nblocks, space_left); | |
167 | printk(KERN_ERR "%s: no way to get more " | |
168 | "journal space in %s\n", __func__, | |
169 | journal->j_devname); | |
170 | WARN_ON(1); | |
23f8b79e DG |
171 | jbd2_journal_abort(journal, 0); |
172 | } | |
a931da6a | 173 | write_lock(&journal->j_state_lock); |
23f8b79e DG |
174 | } else { |
175 | spin_unlock(&journal->j_list_lock); | |
470decc6 DK |
176 | } |
177 | mutex_unlock(&journal->j_checkpoint_mutex); | |
178 | } | |
179 | } | |
180 | ||
470decc6 | 181 | static void |
1a0d3786 | 182 | __flush_batch(journal_t *journal, int *batch_count) |
470decc6 DK |
183 | { |
184 | int i; | |
d3ad8434 | 185 | struct blk_plug plug; |
470decc6 | 186 | |
d3ad8434 | 187 | blk_start_plug(&plug); |
9cb569d6 | 188 | for (i = 0; i < *batch_count; i++) |
d3ad8434 TM |
189 | write_dirty_buffer(journal->j_chkpt_bhs[i], WRITE_SYNC); |
190 | blk_finish_plug(&plug); | |
9cb569d6 | 191 | |
470decc6 | 192 | for (i = 0; i < *batch_count; i++) { |
1a0d3786 | 193 | struct buffer_head *bh = journal->j_chkpt_bhs[i]; |
470decc6 DK |
194 | BUFFER_TRACE(bh, "brelse"); |
195 | __brelse(bh); | |
196 | } | |
197 | *batch_count = 0; | |
198 | } | |
199 | ||
470decc6 DK |
200 | /* |
201 | * Perform an actual checkpoint. We take the first transaction on the | |
202 | * list of transactions to be checkpointed and send all its buffers | |
203 | * to disk. We submit larger chunks of data at once. | |
204 | * | |
205 | * The journal should be locked before calling this function. | |
44519faf | 206 | * Called with j_checkpoint_mutex held. |
470decc6 | 207 | */ |
f7f4bccb | 208 | int jbd2_log_do_checkpoint(journal_t *journal) |
470decc6 | 209 | { |
be1158cc TT |
210 | struct journal_head *jh; |
211 | struct buffer_head *bh; | |
212 | transaction_t *transaction; | |
213 | tid_t this_tid; | |
dc6e8d66 | 214 | int result, batch_count = 0; |
470decc6 DK |
215 | |
216 | jbd_debug(1, "Start checkpoint\n"); | |
217 | ||
218 | /* | |
219 | * First thing: if there are any transactions in the log which | |
220 | * don't need checkpointing, just eliminate them from the | |
221 | * journal straight away. | |
222 | */ | |
f7f4bccb | 223 | result = jbd2_cleanup_journal_tail(journal); |
879c5e6b | 224 | trace_jbd2_checkpoint(journal, result); |
470decc6 DK |
225 | jbd_debug(1, "cleanup_journal_tail returned %d\n", result); |
226 | if (result <= 0) | |
227 | return result; | |
228 | ||
229 | /* | |
230 | * OK, we need to start writing disk blocks. Take one transaction | |
231 | * and write it. | |
232 | */ | |
44519faf | 233 | result = 0; |
470decc6 DK |
234 | spin_lock(&journal->j_list_lock); |
235 | if (!journal->j_checkpoint_transactions) | |
236 | goto out; | |
237 | transaction = journal->j_checkpoint_transactions; | |
8e85fb3f JL |
238 | if (transaction->t_chp_stats.cs_chp_time == 0) |
239 | transaction->t_chp_stats.cs_chp_time = jiffies; | |
470decc6 DK |
240 | this_tid = transaction->t_tid; |
241 | restart: | |
242 | /* | |
243 | * If someone cleaned up this transaction while we slept, we're | |
244 | * done (maybe it's a new transaction, but it fell at the same | |
245 | * address). | |
246 | */ | |
be1158cc TT |
247 | if (journal->j_checkpoint_transactions != transaction || |
248 | transaction->t_tid != this_tid) | |
249 | goto out; | |
470decc6 | 250 | |
be1158cc TT |
251 | /* checkpoint all of the transaction's buffers */ |
252 | while (transaction->t_checkpoint_list) { | |
253 | jh = transaction->t_checkpoint_list; | |
254 | bh = jh2bh(jh); | |
255 | ||
256 | if (buffer_locked(bh)) { | |
257 | spin_unlock(&journal->j_list_lock); | |
258 | get_bh(bh); | |
259 | wait_on_buffer(bh); | |
260 | /* the journal_head may have gone by now */ | |
261 | BUFFER_TRACE(bh, "brelse"); | |
262 | __brelse(bh); | |
263 | goto retry; | |
470decc6 | 264 | } |
be1158cc TT |
265 | if (jh->b_transaction != NULL) { |
266 | transaction_t *t = jh->b_transaction; | |
267 | tid_t tid = t->t_tid; | |
470decc6 | 268 | |
be1158cc TT |
269 | transaction->t_chp_stats.cs_forced_to_close++; |
270 | spin_unlock(&journal->j_list_lock); | |
271 | if (unlikely(journal->j_flags & JBD2_UNMOUNT)) | |
272 | /* | |
273 | * The journal thread is dead; so | |
274 | * starting and waiting for a commit | |
275 | * to finish will cause us to wait for | |
276 | * a _very_ long time. | |
277 | */ | |
278 | printk(KERN_ERR | |
279 | "JBD2: %s: Waiting for Godot: block %llu\n", | |
280 | journal->j_devname, (unsigned long long) bh->b_blocknr); | |
281 | ||
282 | jbd2_log_start_commit(journal, tid); | |
283 | jbd2_log_wait_commit(journal, tid); | |
284 | goto retry; | |
285 | } | |
286 | if (!buffer_dirty(bh)) { | |
287 | if (unlikely(buffer_write_io_error(bh)) && !result) | |
288 | result = -EIO; | |
be1158cc | 289 | BUFFER_TRACE(bh, "remove from checkpoint"); |
0e5ecf0a JK |
290 | if (__jbd2_journal_remove_checkpoint(jh)) |
291 | /* The transaction was released; we're done */ | |
292 | goto out; | |
293 | continue; | |
470decc6 DK |
294 | } |
295 | /* | |
be1158cc TT |
296 | * Important: we are about to write the buffer, and |
297 | * possibly block, while still holding the journal | |
298 | * lock. We cannot afford to let the transaction | |
299 | * logic start messing around with this buffer before | |
300 | * we write it to disk, as that would break | |
301 | * recoverability. | |
470decc6 | 302 | */ |
be1158cc TT |
303 | BUFFER_TRACE(bh, "queue"); |
304 | get_bh(bh); | |
305 | J_ASSERT_BH(bh, !buffer_jwrite(bh)); | |
306 | journal->j_chkpt_bhs[batch_count++] = bh; | |
307 | __buffer_relink_io(jh); | |
308 | transaction->t_chp_stats.cs_written++; | |
309 | if ((batch_count == JBD2_NR_BATCH) || | |
310 | need_resched() || | |
311 | spin_needbreak(&journal->j_list_lock)) | |
312 | goto unlock_and_flush; | |
470decc6 | 313 | } |
be1158cc TT |
314 | |
315 | if (batch_count) { | |
316 | unlock_and_flush: | |
317 | spin_unlock(&journal->j_list_lock); | |
318 | retry: | |
319 | if (batch_count) | |
320 | __flush_batch(journal, &batch_count); | |
321 | spin_lock(&journal->j_list_lock); | |
322 | goto restart; | |
323 | } | |
324 | ||
325 | /* | |
326 | * Now we issued all of the transaction's buffers, let's deal | |
327 | * with the buffers that are out for I/O. | |
328 | */ | |
88fe1acb TT |
329 | restart2: |
330 | /* Did somebody clean up the transaction in the meanwhile? */ | |
331 | if (journal->j_checkpoint_transactions != transaction || | |
332 | transaction->t_tid != this_tid) | |
333 | goto out; | |
334 | ||
dc6e8d66 | 335 | while (transaction->t_checkpoint_io_list) { |
88fe1acb TT |
336 | jh = transaction->t_checkpoint_io_list; |
337 | bh = jh2bh(jh); | |
88fe1acb TT |
338 | if (buffer_locked(bh)) { |
339 | spin_unlock(&journal->j_list_lock); | |
dc6e8d66 | 340 | get_bh(bh); |
88fe1acb TT |
341 | wait_on_buffer(bh); |
342 | /* the journal_head may have gone by now */ | |
343 | BUFFER_TRACE(bh, "brelse"); | |
344 | __brelse(bh); | |
345 | spin_lock(&journal->j_list_lock); | |
346 | goto restart2; | |
347 | } | |
348 | if (unlikely(buffer_write_io_error(bh)) && !result) | |
349 | result = -EIO; | |
350 | ||
351 | /* | |
352 | * Now in whatever state the buffer currently is, we | |
353 | * know that it has been written out and so we can | |
354 | * drop it from the list | |
355 | */ | |
dc6e8d66 TT |
356 | if (__jbd2_journal_remove_checkpoint(jh)) |
357 | break; | |
88fe1acb | 358 | } |
470decc6 DK |
359 | out: |
360 | spin_unlock(&journal->j_list_lock); | |
470decc6 | 361 | if (result < 0) |
44519faf HK |
362 | jbd2_journal_abort(journal, result); |
363 | else | |
364 | result = jbd2_cleanup_journal_tail(journal); | |
365 | ||
366 | return (result < 0) ? result : 0; | |
470decc6 DK |
367 | } |
368 | ||
369 | /* | |
370 | * Check the list of checkpoint transactions for the journal to see if | |
371 | * we have already got rid of any since the last update of the log tail | |
372 | * in the journal superblock. If so, we can instantly roll the | |
373 | * superblock forward to remove those transactions from the log. | |
374 | * | |
375 | * Return <0 on error, 0 on success, 1 if there was nothing to clean up. | |
376 | * | |
377 | * Called with the journal lock held. | |
378 | * | |
379 | * This is the only part of the journaling code which really needs to be | |
380 | * aware of transaction aborts. Checkpointing involves writing to the | |
381 | * main filesystem area rather than to the journal, so it can proceed | |
44519faf HK |
382 | * even in abort state, but we must not update the super block if |
383 | * checkpointing may have failed. Otherwise, we would lose some metadata | |
384 | * buffers which should be written-back to the filesystem. | |
470decc6 DK |
385 | */ |
386 | ||
f7f4bccb | 387 | int jbd2_cleanup_journal_tail(journal_t *journal) |
470decc6 | 388 | { |
470decc6 | 389 | tid_t first_tid; |
79feb521 | 390 | unsigned long blocknr; |
470decc6 | 391 | |
44519faf | 392 | if (is_journal_aborted(journal)) |
6f6a6fda | 393 | return -EIO; |
44519faf | 394 | |
79feb521 | 395 | if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr)) |
470decc6 | 396 | return 1; |
79feb521 | 397 | J_ASSERT(blocknr != 0); |
cc3e1bea TT |
398 | |
399 | /* | |
79feb521 JK |
400 | * We need to make sure that any blocks that were recently written out |
401 | * --- perhaps by jbd2_log_do_checkpoint() --- are flushed out before | |
402 | * we drop the transactions from the journal. It's unlikely this will | |
403 | * be necessary, especially with an appropriately sized journal, but we | |
404 | * need this to guarantee correctness. Fortunately | |
405 | * jbd2_cleanup_journal_tail() doesn't get called all that often. | |
cc3e1bea | 406 | */ |
79feb521 | 407 | if (journal->j_flags & JBD2_BARRIER) |
b4f1afcd | 408 | blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL); |
79feb521 | 409 | |
6f6a6fda | 410 | return __jbd2_update_log_tail(journal, first_tid, blocknr); |
470decc6 DK |
411 | } |
412 | ||
413 | ||
414 | /* Checkpoint list management */ | |
415 | ||
416 | /* | |
417 | * journal_clean_one_cp_list | |
418 | * | |
de1b7941 | 419 | * Find all the written-back checkpoint buffers in the given list and |
841df7df | 420 | * release them. If 'destroy' is set, clean all buffers unconditionally. |
470decc6 | 421 | * |
470decc6 | 422 | * Called with j_list_lock held. |
50849db3 | 423 | * Returns 1 if we freed the transaction, 0 otherwise. |
470decc6 | 424 | */ |
841df7df | 425 | static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy) |
470decc6 DK |
426 | { |
427 | struct journal_head *last_jh; | |
428 | struct journal_head *next_jh = jh; | |
50849db3 | 429 | int ret; |
470decc6 | 430 | |
470decc6 DK |
431 | if (!jh) |
432 | return 0; | |
433 | ||
434 | last_jh = jh->b_cpprev; | |
435 | do { | |
436 | jh = next_jh; | |
437 | next_jh = jh->b_cpnext; | |
841df7df JK |
438 | if (!destroy) |
439 | ret = __try_to_free_cp_buf(jh); | |
440 | else | |
441 | ret = __jbd2_journal_remove_checkpoint(jh) + 1; | |
cc97f1a7 | 442 | if (!ret) |
33d14975 | 443 | return 0; |
50849db3 JK |
444 | if (ret == 2) |
445 | return 1; | |
470decc6 DK |
446 | /* |
447 | * This function only frees up some memory | |
448 | * if possible so we dont have an obligation | |
449 | * to finish processing. Bail out if preemption | |
450 | * requested: | |
451 | */ | |
452 | if (need_resched()) | |
33d14975 | 453 | return 0; |
470decc6 DK |
454 | } while (jh != last_jh); |
455 | ||
33d14975 | 456 | return 0; |
470decc6 DK |
457 | } |
458 | ||
459 | /* | |
460 | * journal_clean_checkpoint_list | |
461 | * | |
462 | * Find all the written-back checkpoint buffers in the journal and release them. | |
841df7df | 463 | * If 'destroy' is set, release all buffers unconditionally. |
470decc6 | 464 | * |
470decc6 | 465 | * Called with j_list_lock held. |
470decc6 | 466 | */ |
841df7df | 467 | void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy) |
470decc6 DK |
468 | { |
469 | transaction_t *transaction, *last_transaction, *next_transaction; | |
cc97f1a7 | 470 | int ret; |
470decc6 DK |
471 | |
472 | transaction = journal->j_checkpoint_transactions; | |
473 | if (!transaction) | |
50849db3 | 474 | return; |
470decc6 DK |
475 | |
476 | last_transaction = transaction->t_cpprev; | |
477 | next_transaction = transaction; | |
478 | do { | |
479 | transaction = next_transaction; | |
480 | next_transaction = transaction->t_cpnext; | |
841df7df JK |
481 | ret = journal_clean_one_cp_list(transaction->t_checkpoint_list, |
482 | destroy); | |
470decc6 DK |
483 | /* |
484 | * This function only frees up some memory if possible so we | |
485 | * dont have an obligation to finish processing. Bail out if | |
486 | * preemption requested: | |
487 | */ | |
50849db3 JK |
488 | if (need_resched()) |
489 | return; | |
490 | if (ret) | |
470decc6 DK |
491 | continue; |
492 | /* | |
493 | * It is essential that we are as careful as in the case of | |
494 | * t_checkpoint_list with removing the buffer from the list as | |
495 | * we can possibly see not yet submitted buffers on io_list | |
496 | */ | |
50849db3 | 497 | ret = journal_clean_one_cp_list(transaction-> |
841df7df | 498 | t_checkpoint_io_list, destroy); |
50849db3 JK |
499 | if (need_resched()) |
500 | return; | |
501 | /* | |
502 | * Stop scanning if we couldn't free the transaction. This | |
503 | * avoids pointless scanning of transactions which still | |
504 | * weren't checkpointed. | |
505 | */ | |
506 | if (!ret) | |
507 | return; | |
470decc6 | 508 | } while (transaction != last_transaction); |
470decc6 DK |
509 | } |
510 | ||
841df7df JK |
511 | /* |
512 | * Remove buffers from all checkpoint lists as journal is aborted and we just | |
513 | * need to free memory | |
514 | */ | |
515 | void jbd2_journal_destroy_checkpoint(journal_t *journal) | |
516 | { | |
517 | /* | |
518 | * We loop because __jbd2_journal_clean_checkpoint_list() may abort | |
519 | * early due to a need of rescheduling. | |
520 | */ | |
521 | while (1) { | |
522 | spin_lock(&journal->j_list_lock); | |
523 | if (!journal->j_checkpoint_transactions) { | |
524 | spin_unlock(&journal->j_list_lock); | |
525 | break; | |
526 | } | |
527 | __jbd2_journal_clean_checkpoint_list(journal, true); | |
528 | spin_unlock(&journal->j_list_lock); | |
529 | cond_resched(); | |
530 | } | |
531 | } | |
532 | ||
470decc6 DK |
533 | /* |
534 | * journal_remove_checkpoint: called after a buffer has been committed | |
535 | * to disk (either by being write-back flushed to disk, or being | |
536 | * committed to the log). | |
537 | * | |
538 | * We cannot safely clean a transaction out of the log until all of the | |
539 | * buffer updates committed in that transaction have safely been stored | |
540 | * elsewhere on disk. To achieve this, all of the buffers in a | |
541 | * transaction need to be maintained on the transaction's checkpoint | |
542 | * lists until they have been rewritten, at which point this function is | |
543 | * called to remove the buffer from the existing transaction's | |
544 | * checkpoint lists. | |
545 | * | |
546 | * The function returns 1 if it frees the transaction, 0 otherwise. | |
de1b7941 | 547 | * The function can free jh and bh. |
470decc6 | 548 | * |
470decc6 | 549 | * This function is called with j_list_lock held. |
470decc6 | 550 | */ |
f7f4bccb | 551 | int __jbd2_journal_remove_checkpoint(struct journal_head *jh) |
470decc6 | 552 | { |
bf699327 | 553 | struct transaction_chp_stats_s *stats; |
470decc6 DK |
554 | transaction_t *transaction; |
555 | journal_t *journal; | |
556 | int ret = 0; | |
557 | ||
558 | JBUFFER_TRACE(jh, "entry"); | |
559 | ||
560 | if ((transaction = jh->b_cp_transaction) == NULL) { | |
561 | JBUFFER_TRACE(jh, "not on transaction"); | |
562 | goto out; | |
563 | } | |
564 | journal = transaction->t_journal; | |
565 | ||
de1b7941 | 566 | JBUFFER_TRACE(jh, "removing from transaction"); |
470decc6 DK |
567 | __buffer_unlink(jh); |
568 | jh->b_cp_transaction = NULL; | |
de1b7941 | 569 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
570 | |
571 | if (transaction->t_checkpoint_list != NULL || | |
572 | transaction->t_checkpoint_io_list != NULL) | |
573 | goto out; | |
470decc6 DK |
574 | |
575 | /* | |
576 | * There is one special case to worry about: if we have just pulled the | |
f5a7a6b0 JK |
577 | * buffer off a running or committing transaction's checkpoing list, |
578 | * then even if the checkpoint list is empty, the transaction obviously | |
579 | * cannot be dropped! | |
470decc6 | 580 | * |
f5a7a6b0 | 581 | * The locking here around t_state is a bit sleazy. |
f7f4bccb | 582 | * See the comment at the end of jbd2_journal_commit_transaction(). |
470decc6 | 583 | */ |
de1b7941 | 584 | if (transaction->t_state != T_FINISHED) |
470decc6 | 585 | goto out; |
470decc6 DK |
586 | |
587 | /* OK, that was the last buffer for the transaction: we can now | |
588 | safely remove this transaction from the log */ | |
bf699327 TT |
589 | stats = &transaction->t_chp_stats; |
590 | if (stats->cs_chp_time) | |
591 | stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time, | |
592 | jiffies); | |
593 | trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev, | |
594 | transaction->t_tid, stats); | |
470decc6 | 595 | |
f7f4bccb | 596 | __jbd2_journal_drop_transaction(journal, transaction); |
0c2022ec | 597 | jbd2_journal_free_transaction(transaction); |
470decc6 DK |
598 | ret = 1; |
599 | out: | |
470decc6 DK |
600 | return ret; |
601 | } | |
602 | ||
603 | /* | |
604 | * journal_insert_checkpoint: put a committed buffer onto a checkpoint | |
605 | * list so that we know when it is safe to clean the transaction out of | |
606 | * the log. | |
607 | * | |
608 | * Called with the journal locked. | |
609 | * Called with j_list_lock held. | |
610 | */ | |
f7f4bccb | 611 | void __jbd2_journal_insert_checkpoint(struct journal_head *jh, |
470decc6 DK |
612 | transaction_t *transaction) |
613 | { | |
614 | JBUFFER_TRACE(jh, "entry"); | |
615 | J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh))); | |
616 | J_ASSERT_JH(jh, jh->b_cp_transaction == NULL); | |
617 | ||
de1b7941 JK |
618 | /* Get reference for checkpointing transaction */ |
619 | jbd2_journal_grab_journal_head(jh2bh(jh)); | |
470decc6 DK |
620 | jh->b_cp_transaction = transaction; |
621 | ||
622 | if (!transaction->t_checkpoint_list) { | |
623 | jh->b_cpnext = jh->b_cpprev = jh; | |
624 | } else { | |
625 | jh->b_cpnext = transaction->t_checkpoint_list; | |
626 | jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev; | |
627 | jh->b_cpprev->b_cpnext = jh; | |
628 | jh->b_cpnext->b_cpprev = jh; | |
629 | } | |
630 | transaction->t_checkpoint_list = jh; | |
631 | } | |
632 | ||
633 | /* | |
634 | * We've finished with this transaction structure: adios... | |
635 | * | |
636 | * The transaction must have no links except for the checkpoint by this | |
637 | * point. | |
638 | * | |
639 | * Called with the journal locked. | |
640 | * Called with j_list_lock held. | |
641 | */ | |
642 | ||
f7f4bccb | 643 | void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
644 | { |
645 | assert_spin_locked(&journal->j_list_lock); | |
646 | if (transaction->t_cpnext) { | |
647 | transaction->t_cpnext->t_cpprev = transaction->t_cpprev; | |
648 | transaction->t_cpprev->t_cpnext = transaction->t_cpnext; | |
649 | if (journal->j_checkpoint_transactions == transaction) | |
650 | journal->j_checkpoint_transactions = | |
651 | transaction->t_cpnext; | |
652 | if (journal->j_checkpoint_transactions == transaction) | |
653 | journal->j_checkpoint_transactions = NULL; | |
654 | } | |
655 | ||
656 | J_ASSERT(transaction->t_state == T_FINISHED); | |
657 | J_ASSERT(transaction->t_buffers == NULL); | |
470decc6 | 658 | J_ASSERT(transaction->t_forget == NULL); |
470decc6 | 659 | J_ASSERT(transaction->t_shadow_list == NULL); |
470decc6 DK |
660 | J_ASSERT(transaction->t_checkpoint_list == NULL); |
661 | J_ASSERT(transaction->t_checkpoint_io_list == NULL); | |
a51dca9c | 662 | J_ASSERT(atomic_read(&transaction->t_updates) == 0); |
470decc6 DK |
663 | J_ASSERT(journal->j_committing_transaction != transaction); |
664 | J_ASSERT(journal->j_running_transaction != transaction); | |
665 | ||
2201c590 SA |
666 | trace_jbd2_drop_transaction(journal, transaction); |
667 | ||
470decc6 | 668 | jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid); |
470decc6 | 669 | } |