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f5166768 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
470decc6 | 2 | /* |
58862699 | 3 | * linux/fs/jbd2/checkpoint.c |
470decc6 DK |
4 | * |
5 | * Written by Stephen C. Tweedie <sct@redhat.com>, 1999 | |
6 | * | |
7 | * Copyright 1999 Red Hat Software --- All Rights Reserved | |
8 | * | |
470decc6 DK |
9 | * Checkpoint routines for the generic filesystem journaling code. |
10 | * Part of the ext2fs journaling system. | |
11 | * | |
12 | * Checkpointing is the process of ensuring that a section of the log is | |
13 | * committed fully to disk, so that that portion of the log can be | |
14 | * reused. | |
15 | */ | |
16 | ||
17 | #include <linux/time.h> | |
18 | #include <linux/fs.h> | |
f7f4bccb | 19 | #include <linux/jbd2.h> |
470decc6 DK |
20 | #include <linux/errno.h> |
21 | #include <linux/slab.h> | |
cc3e1bea | 22 | #include <linux/blkdev.h> |
879c5e6b | 23 | #include <trace/events/jbd2.h> |
470decc6 DK |
24 | |
25 | /* | |
26 | * Unlink a buffer from a transaction checkpoint list. | |
27 | * | |
28 | * Called with j_list_lock held. | |
29 | */ | |
30 | static inline void __buffer_unlink_first(struct journal_head *jh) | |
31 | { | |
32 | transaction_t *transaction = jh->b_cp_transaction; | |
33 | ||
34 | jh->b_cpnext->b_cpprev = jh->b_cpprev; | |
35 | jh->b_cpprev->b_cpnext = jh->b_cpnext; | |
36 | if (transaction->t_checkpoint_list == jh) { | |
37 | transaction->t_checkpoint_list = jh->b_cpnext; | |
38 | if (transaction->t_checkpoint_list == jh) | |
39 | transaction->t_checkpoint_list = NULL; | |
40 | } | |
41 | } | |
42 | ||
43 | /* | |
44 | * Unlink a buffer from a transaction checkpoint(io) list. | |
45 | * | |
46 | * Called with j_list_lock held. | |
47 | */ | |
48 | static inline void __buffer_unlink(struct journal_head *jh) | |
49 | { | |
50 | transaction_t *transaction = jh->b_cp_transaction; | |
51 | ||
52 | __buffer_unlink_first(jh); | |
53 | if (transaction->t_checkpoint_io_list == jh) { | |
54 | transaction->t_checkpoint_io_list = jh->b_cpnext; | |
55 | if (transaction->t_checkpoint_io_list == jh) | |
56 | transaction->t_checkpoint_io_list = NULL; | |
57 | } | |
58 | } | |
59 | ||
60 | /* | |
61 | * Move a buffer from the checkpoint list to the checkpoint io list | |
62 | * | |
63 | * Called with j_list_lock held | |
64 | */ | |
65 | static inline void __buffer_relink_io(struct journal_head *jh) | |
66 | { | |
67 | transaction_t *transaction = jh->b_cp_transaction; | |
68 | ||
69 | __buffer_unlink_first(jh); | |
70 | ||
71 | if (!transaction->t_checkpoint_io_list) { | |
72 | jh->b_cpnext = jh->b_cpprev = jh; | |
73 | } else { | |
74 | jh->b_cpnext = transaction->t_checkpoint_io_list; | |
75 | jh->b_cpprev = transaction->t_checkpoint_io_list->b_cpprev; | |
76 | jh->b_cpprev->b_cpnext = jh; | |
77 | jh->b_cpnext->b_cpprev = jh; | |
78 | } | |
79 | transaction->t_checkpoint_io_list = jh; | |
80 | } | |
81 | ||
82 | /* | |
83 | * Try to release a checkpointed buffer from its transaction. | |
84 | * Returns 1 if we released it and 2 if we also released the | |
85 | * whole transaction. | |
86 | * | |
87 | * Requires j_list_lock | |
470decc6 DK |
88 | */ |
89 | static int __try_to_free_cp_buf(struct journal_head *jh) | |
90 | { | |
91 | int ret = 0; | |
92 | struct buffer_head *bh = jh2bh(jh); | |
93 | ||
932bb305 | 94 | if (jh->b_transaction == NULL && !buffer_locked(bh) && |
44519faf | 95 | !buffer_dirty(bh) && !buffer_write_io_error(bh)) { |
470decc6 | 96 | JBUFFER_TRACE(jh, "remove from checkpoint list"); |
f7f4bccb | 97 | ret = __jbd2_journal_remove_checkpoint(jh) + 1; |
470decc6 DK |
98 | } |
99 | return ret; | |
100 | } | |
101 | ||
102 | /* | |
f7f4bccb | 103 | * __jbd2_log_wait_for_space: wait until there is space in the journal. |
470decc6 DK |
104 | * |
105 | * Called under j-state_lock *only*. It will be unlocked if we have to wait | |
106 | * for a checkpoint to free up some space in the log. | |
107 | */ | |
f7f4bccb | 108 | void __jbd2_log_wait_for_space(journal_t *journal) |
470decc6 | 109 | { |
8c3f25d8 | 110 | int nblocks, space_left; |
a931da6a | 111 | /* assert_spin_locked(&journal->j_state_lock); */ |
470decc6 | 112 | |
76c39904 JK |
113 | nblocks = jbd2_space_needed(journal); |
114 | while (jbd2_log_space_left(journal) < nblocks) { | |
a931da6a | 115 | write_unlock(&journal->j_state_lock); |
53cf9784 | 116 | mutex_lock_io(&journal->j_checkpoint_mutex); |
470decc6 DK |
117 | |
118 | /* | |
119 | * Test again, another process may have checkpointed while we | |
23f8b79e | 120 | * were waiting for the checkpoint lock. If there are no |
8c3f25d8 TT |
121 | * transactions ready to be checkpointed, try to recover |
122 | * journal space by calling cleanup_journal_tail(), and if | |
123 | * that doesn't work, by waiting for the currently committing | |
124 | * transaction to complete. If there is absolutely no way | |
125 | * to make progress, this is either a BUG or corrupted | |
126 | * filesystem, so abort the journal and leave a stack | |
127 | * trace for forensic evidence. | |
470decc6 | 128 | */ |
a931da6a | 129 | write_lock(&journal->j_state_lock); |
1245799f DM |
130 | if (journal->j_flags & JBD2_ABORT) { |
131 | mutex_unlock(&journal->j_checkpoint_mutex); | |
132 | return; | |
133 | } | |
23f8b79e | 134 | spin_lock(&journal->j_list_lock); |
76c39904 JK |
135 | nblocks = jbd2_space_needed(journal); |
136 | space_left = jbd2_log_space_left(journal); | |
8c3f25d8 | 137 | if (space_left < nblocks) { |
23f8b79e | 138 | int chkpt = journal->j_checkpoint_transactions != NULL; |
8c3f25d8 | 139 | tid_t tid = 0; |
23f8b79e | 140 | |
8c3f25d8 TT |
141 | if (journal->j_committing_transaction) |
142 | tid = journal->j_committing_transaction->t_tid; | |
23f8b79e | 143 | spin_unlock(&journal->j_list_lock); |
a931da6a | 144 | write_unlock(&journal->j_state_lock); |
23f8b79e DG |
145 | if (chkpt) { |
146 | jbd2_log_do_checkpoint(journal); | |
8c3f25d8 TT |
147 | } else if (jbd2_cleanup_journal_tail(journal) == 0) { |
148 | /* We were able to recover space; yay! */ | |
149 | ; | |
150 | } else if (tid) { | |
0ef54180 PG |
151 | /* |
152 | * jbd2_journal_commit_transaction() may want | |
153 | * to take the checkpoint_mutex if JBD2_FLUSHED | |
154 | * is set. So we need to temporarily drop it. | |
155 | */ | |
156 | mutex_unlock(&journal->j_checkpoint_mutex); | |
8c3f25d8 | 157 | jbd2_log_wait_commit(journal, tid); |
0ef54180 PG |
158 | write_lock(&journal->j_state_lock); |
159 | continue; | |
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 | } | |
a931da6a | 170 | write_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 | ||
470decc6 | 178 | static void |
1a0d3786 | 179 | __flush_batch(journal_t *journal, int *batch_count) |
470decc6 DK |
180 | { |
181 | int i; | |
d3ad8434 | 182 | struct blk_plug plug; |
470decc6 | 183 | |
d3ad8434 | 184 | blk_start_plug(&plug); |
9cb569d6 | 185 | for (i = 0; i < *batch_count; i++) |
70fd7614 | 186 | write_dirty_buffer(journal->j_chkpt_bhs[i], REQ_SYNC); |
d3ad8434 | 187 | blk_finish_plug(&plug); |
9cb569d6 | 188 | |
470decc6 | 189 | for (i = 0; i < *batch_count; i++) { |
1a0d3786 | 190 | struct buffer_head *bh = journal->j_chkpt_bhs[i]; |
470decc6 DK |
191 | BUFFER_TRACE(bh, "brelse"); |
192 | __brelse(bh); | |
193 | } | |
194 | *batch_count = 0; | |
195 | } | |
196 | ||
470decc6 DK |
197 | /* |
198 | * Perform an actual checkpoint. We take the first transaction on the | |
199 | * list of transactions to be checkpointed and send all its buffers | |
200 | * to disk. We submit larger chunks of data at once. | |
201 | * | |
202 | * The journal should be locked before calling this function. | |
44519faf | 203 | * Called with j_checkpoint_mutex held. |
470decc6 | 204 | */ |
f7f4bccb | 205 | int jbd2_log_do_checkpoint(journal_t *journal) |
470decc6 | 206 | { |
be1158cc TT |
207 | struct journal_head *jh; |
208 | struct buffer_head *bh; | |
209 | transaction_t *transaction; | |
210 | tid_t this_tid; | |
dc6e8d66 | 211 | int result, batch_count = 0; |
470decc6 DK |
212 | |
213 | jbd_debug(1, "Start checkpoint\n"); | |
214 | ||
215 | /* | |
216 | * First thing: if there are any transactions in the log which | |
217 | * don't need checkpointing, just eliminate them from the | |
218 | * journal straight away. | |
219 | */ | |
f7f4bccb | 220 | result = jbd2_cleanup_journal_tail(journal); |
879c5e6b | 221 | trace_jbd2_checkpoint(journal, result); |
470decc6 DK |
222 | jbd_debug(1, "cleanup_journal_tail returned %d\n", result); |
223 | if (result <= 0) | |
224 | return result; | |
225 | ||
226 | /* | |
227 | * OK, we need to start writing disk blocks. Take one transaction | |
228 | * and write it. | |
229 | */ | |
44519faf | 230 | result = 0; |
470decc6 DK |
231 | spin_lock(&journal->j_list_lock); |
232 | if (!journal->j_checkpoint_transactions) | |
233 | goto out; | |
234 | transaction = journal->j_checkpoint_transactions; | |
8e85fb3f JL |
235 | if (transaction->t_chp_stats.cs_chp_time == 0) |
236 | transaction->t_chp_stats.cs_chp_time = jiffies; | |
470decc6 DK |
237 | this_tid = transaction->t_tid; |
238 | restart: | |
239 | /* | |
240 | * If someone cleaned up this transaction while we slept, we're | |
241 | * done (maybe it's a new transaction, but it fell at the same | |
242 | * address). | |
243 | */ | |
be1158cc TT |
244 | if (journal->j_checkpoint_transactions != transaction || |
245 | transaction->t_tid != this_tid) | |
246 | goto out; | |
470decc6 | 247 | |
be1158cc TT |
248 | /* checkpoint all of the transaction's buffers */ |
249 | while (transaction->t_checkpoint_list) { | |
250 | jh = transaction->t_checkpoint_list; | |
251 | bh = jh2bh(jh); | |
252 | ||
253 | if (buffer_locked(bh)) { | |
be1158cc | 254 | get_bh(bh); |
ccd3c437 | 255 | spin_unlock(&journal->j_list_lock); |
be1158cc TT |
256 | wait_on_buffer(bh); |
257 | /* the journal_head may have gone by now */ | |
258 | BUFFER_TRACE(bh, "brelse"); | |
259 | __brelse(bh); | |
260 | goto retry; | |
470decc6 | 261 | } |
be1158cc TT |
262 | if (jh->b_transaction != NULL) { |
263 | transaction_t *t = jh->b_transaction; | |
264 | tid_t tid = t->t_tid; | |
470decc6 | 265 | |
be1158cc TT |
266 | transaction->t_chp_stats.cs_forced_to_close++; |
267 | spin_unlock(&journal->j_list_lock); | |
268 | if (unlikely(journal->j_flags & JBD2_UNMOUNT)) | |
269 | /* | |
270 | * The journal thread is dead; so | |
271 | * starting and waiting for a commit | |
272 | * to finish will cause us to wait for | |
273 | * a _very_ long time. | |
274 | */ | |
275 | printk(KERN_ERR | |
276 | "JBD2: %s: Waiting for Godot: block %llu\n", | |
277 | journal->j_devname, (unsigned long long) bh->b_blocknr); | |
278 | ||
53cf9784 XW |
279 | if (batch_count) |
280 | __flush_batch(journal, &batch_count); | |
be1158cc | 281 | jbd2_log_start_commit(journal, tid); |
53cf9784 XW |
282 | /* |
283 | * jbd2_journal_commit_transaction() may want | |
284 | * to take the checkpoint_mutex if JBD2_FLUSHED | |
285 | * is set, jbd2_update_log_tail() called by | |
286 | * jbd2_journal_commit_transaction() may also take | |
287 | * checkpoint_mutex. So we need to temporarily | |
288 | * drop it. | |
289 | */ | |
290 | mutex_unlock(&journal->j_checkpoint_mutex); | |
be1158cc | 291 | jbd2_log_wait_commit(journal, tid); |
53cf9784 XW |
292 | mutex_lock_io(&journal->j_checkpoint_mutex); |
293 | spin_lock(&journal->j_list_lock); | |
294 | goto restart; | |
be1158cc TT |
295 | } |
296 | if (!buffer_dirty(bh)) { | |
297 | if (unlikely(buffer_write_io_error(bh)) && !result) | |
298 | result = -EIO; | |
be1158cc | 299 | BUFFER_TRACE(bh, "remove from checkpoint"); |
0e5ecf0a JK |
300 | if (__jbd2_journal_remove_checkpoint(jh)) |
301 | /* The transaction was released; we're done */ | |
302 | goto out; | |
303 | continue; | |
470decc6 DK |
304 | } |
305 | /* | |
be1158cc TT |
306 | * Important: we are about to write the buffer, and |
307 | * possibly block, while still holding the journal | |
308 | * lock. We cannot afford to let the transaction | |
309 | * logic start messing around with this buffer before | |
310 | * we write it to disk, as that would break | |
311 | * recoverability. | |
470decc6 | 312 | */ |
be1158cc TT |
313 | BUFFER_TRACE(bh, "queue"); |
314 | get_bh(bh); | |
315 | J_ASSERT_BH(bh, !buffer_jwrite(bh)); | |
316 | journal->j_chkpt_bhs[batch_count++] = bh; | |
317 | __buffer_relink_io(jh); | |
318 | transaction->t_chp_stats.cs_written++; | |
319 | if ((batch_count == JBD2_NR_BATCH) || | |
320 | need_resched() || | |
321 | spin_needbreak(&journal->j_list_lock)) | |
322 | goto unlock_and_flush; | |
470decc6 | 323 | } |
be1158cc TT |
324 | |
325 | if (batch_count) { | |
326 | unlock_and_flush: | |
327 | spin_unlock(&journal->j_list_lock); | |
328 | retry: | |
329 | if (batch_count) | |
330 | __flush_batch(journal, &batch_count); | |
331 | spin_lock(&journal->j_list_lock); | |
332 | goto restart; | |
333 | } | |
334 | ||
335 | /* | |
336 | * Now we issued all of the transaction's buffers, let's deal | |
337 | * with the buffers that are out for I/O. | |
338 | */ | |
88fe1acb TT |
339 | restart2: |
340 | /* Did somebody clean up the transaction in the meanwhile? */ | |
341 | if (journal->j_checkpoint_transactions != transaction || | |
342 | transaction->t_tid != this_tid) | |
343 | goto out; | |
344 | ||
dc6e8d66 | 345 | while (transaction->t_checkpoint_io_list) { |
88fe1acb TT |
346 | jh = transaction->t_checkpoint_io_list; |
347 | bh = jh2bh(jh); | |
88fe1acb | 348 | if (buffer_locked(bh)) { |
dc6e8d66 | 349 | get_bh(bh); |
ccd3c437 | 350 | spin_unlock(&journal->j_list_lock); |
88fe1acb TT |
351 | wait_on_buffer(bh); |
352 | /* the journal_head may have gone by now */ | |
353 | BUFFER_TRACE(bh, "brelse"); | |
354 | __brelse(bh); | |
355 | spin_lock(&journal->j_list_lock); | |
356 | goto restart2; | |
357 | } | |
358 | if (unlikely(buffer_write_io_error(bh)) && !result) | |
359 | result = -EIO; | |
360 | ||
361 | /* | |
362 | * Now in whatever state the buffer currently is, we | |
363 | * know that it has been written out and so we can | |
364 | * drop it from the list | |
365 | */ | |
dc6e8d66 TT |
366 | if (__jbd2_journal_remove_checkpoint(jh)) |
367 | break; | |
88fe1acb | 368 | } |
470decc6 DK |
369 | out: |
370 | spin_unlock(&journal->j_list_lock); | |
470decc6 | 371 | if (result < 0) |
44519faf HK |
372 | jbd2_journal_abort(journal, result); |
373 | else | |
374 | result = jbd2_cleanup_journal_tail(journal); | |
375 | ||
376 | return (result < 0) ? result : 0; | |
470decc6 DK |
377 | } |
378 | ||
379 | /* | |
380 | * Check the list of checkpoint transactions for the journal to see if | |
381 | * we have already got rid of any since the last update of the log tail | |
382 | * in the journal superblock. If so, we can instantly roll the | |
383 | * superblock forward to remove those transactions from the log. | |
384 | * | |
385 | * Return <0 on error, 0 on success, 1 if there was nothing to clean up. | |
386 | * | |
387 | * Called with the journal lock held. | |
388 | * | |
389 | * This is the only part of the journaling code which really needs to be | |
390 | * aware of transaction aborts. Checkpointing involves writing to the | |
391 | * main filesystem area rather than to the journal, so it can proceed | |
44519faf HK |
392 | * even in abort state, but we must not update the super block if |
393 | * checkpointing may have failed. Otherwise, we would lose some metadata | |
394 | * buffers which should be written-back to the filesystem. | |
470decc6 DK |
395 | */ |
396 | ||
f7f4bccb | 397 | int jbd2_cleanup_journal_tail(journal_t *journal) |
470decc6 | 398 | { |
470decc6 | 399 | tid_t first_tid; |
79feb521 | 400 | unsigned long blocknr; |
470decc6 | 401 | |
44519faf | 402 | if (is_journal_aborted(journal)) |
6f6a6fda | 403 | return -EIO; |
44519faf | 404 | |
79feb521 | 405 | if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr)) |
470decc6 | 406 | return 1; |
79feb521 | 407 | J_ASSERT(blocknr != 0); |
cc3e1bea TT |
408 | |
409 | /* | |
79feb521 JK |
410 | * We need to make sure that any blocks that were recently written out |
411 | * --- perhaps by jbd2_log_do_checkpoint() --- are flushed out before | |
412 | * we drop the transactions from the journal. It's unlikely this will | |
413 | * be necessary, especially with an appropriately sized journal, but we | |
414 | * need this to guarantee correctness. Fortunately | |
415 | * jbd2_cleanup_journal_tail() doesn't get called all that often. | |
cc3e1bea | 416 | */ |
79feb521 | 417 | if (journal->j_flags & JBD2_BARRIER) |
b4f1afcd | 418 | blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL); |
79feb521 | 419 | |
6f6a6fda | 420 | return __jbd2_update_log_tail(journal, first_tid, blocknr); |
470decc6 DK |
421 | } |
422 | ||
423 | ||
424 | /* Checkpoint list management */ | |
425 | ||
426 | /* | |
427 | * journal_clean_one_cp_list | |
428 | * | |
de1b7941 | 429 | * Find all the written-back checkpoint buffers in the given list and |
841df7df | 430 | * release them. If 'destroy' is set, clean all buffers unconditionally. |
470decc6 | 431 | * |
470decc6 | 432 | * Called with j_list_lock held. |
50849db3 | 433 | * Returns 1 if we freed the transaction, 0 otherwise. |
470decc6 | 434 | */ |
841df7df | 435 | static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy) |
470decc6 DK |
436 | { |
437 | struct journal_head *last_jh; | |
438 | struct journal_head *next_jh = jh; | |
50849db3 | 439 | int ret; |
470decc6 | 440 | |
470decc6 DK |
441 | if (!jh) |
442 | return 0; | |
443 | ||
444 | last_jh = jh->b_cpprev; | |
445 | do { | |
446 | jh = next_jh; | |
447 | next_jh = jh->b_cpnext; | |
841df7df JK |
448 | if (!destroy) |
449 | ret = __try_to_free_cp_buf(jh); | |
450 | else | |
451 | ret = __jbd2_journal_remove_checkpoint(jh) + 1; | |
cc97f1a7 | 452 | if (!ret) |
33d14975 | 453 | return 0; |
50849db3 JK |
454 | if (ret == 2) |
455 | return 1; | |
470decc6 DK |
456 | /* |
457 | * This function only frees up some memory | |
458 | * if possible so we dont have an obligation | |
459 | * to finish processing. Bail out if preemption | |
460 | * requested: | |
461 | */ | |
462 | if (need_resched()) | |
33d14975 | 463 | return 0; |
470decc6 DK |
464 | } while (jh != last_jh); |
465 | ||
33d14975 | 466 | return 0; |
470decc6 DK |
467 | } |
468 | ||
469 | /* | |
470 | * journal_clean_checkpoint_list | |
471 | * | |
472 | * Find all the written-back checkpoint buffers in the journal and release them. | |
841df7df | 473 | * If 'destroy' is set, release all buffers unconditionally. |
470decc6 | 474 | * |
470decc6 | 475 | * Called with j_list_lock held. |
470decc6 | 476 | */ |
841df7df | 477 | void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy) |
470decc6 DK |
478 | { |
479 | transaction_t *transaction, *last_transaction, *next_transaction; | |
cc97f1a7 | 480 | int ret; |
470decc6 DK |
481 | |
482 | transaction = journal->j_checkpoint_transactions; | |
483 | if (!transaction) | |
50849db3 | 484 | return; |
470decc6 DK |
485 | |
486 | last_transaction = transaction->t_cpprev; | |
487 | next_transaction = transaction; | |
488 | do { | |
489 | transaction = next_transaction; | |
490 | next_transaction = transaction->t_cpnext; | |
841df7df JK |
491 | ret = journal_clean_one_cp_list(transaction->t_checkpoint_list, |
492 | destroy); | |
470decc6 DK |
493 | /* |
494 | * This function only frees up some memory if possible so we | |
495 | * dont have an obligation to finish processing. Bail out if | |
496 | * preemption requested: | |
497 | */ | |
50849db3 JK |
498 | if (need_resched()) |
499 | return; | |
500 | if (ret) | |
470decc6 DK |
501 | continue; |
502 | /* | |
503 | * It is essential that we are as careful as in the case of | |
504 | * t_checkpoint_list with removing the buffer from the list as | |
505 | * we can possibly see not yet submitted buffers on io_list | |
506 | */ | |
50849db3 | 507 | ret = journal_clean_one_cp_list(transaction-> |
841df7df | 508 | t_checkpoint_io_list, destroy); |
50849db3 JK |
509 | if (need_resched()) |
510 | return; | |
511 | /* | |
512 | * Stop scanning if we couldn't free the transaction. This | |
513 | * avoids pointless scanning of transactions which still | |
514 | * weren't checkpointed. | |
515 | */ | |
516 | if (!ret) | |
517 | return; | |
470decc6 | 518 | } while (transaction != last_transaction); |
470decc6 DK |
519 | } |
520 | ||
841df7df JK |
521 | /* |
522 | * Remove buffers from all checkpoint lists as journal is aborted and we just | |
523 | * need to free memory | |
524 | */ | |
525 | void jbd2_journal_destroy_checkpoint(journal_t *journal) | |
526 | { | |
527 | /* | |
528 | * We loop because __jbd2_journal_clean_checkpoint_list() may abort | |
529 | * early due to a need of rescheduling. | |
530 | */ | |
531 | while (1) { | |
532 | spin_lock(&journal->j_list_lock); | |
533 | if (!journal->j_checkpoint_transactions) { | |
534 | spin_unlock(&journal->j_list_lock); | |
535 | break; | |
536 | } | |
537 | __jbd2_journal_clean_checkpoint_list(journal, true); | |
538 | spin_unlock(&journal->j_list_lock); | |
539 | cond_resched(); | |
540 | } | |
541 | } | |
542 | ||
470decc6 DK |
543 | /* |
544 | * journal_remove_checkpoint: called after a buffer has been committed | |
545 | * to disk (either by being write-back flushed to disk, or being | |
546 | * committed to the log). | |
547 | * | |
548 | * We cannot safely clean a transaction out of the log until all of the | |
549 | * buffer updates committed in that transaction have safely been stored | |
550 | * elsewhere on disk. To achieve this, all of the buffers in a | |
551 | * transaction need to be maintained on the transaction's checkpoint | |
552 | * lists until they have been rewritten, at which point this function is | |
553 | * called to remove the buffer from the existing transaction's | |
554 | * checkpoint lists. | |
555 | * | |
556 | * The function returns 1 if it frees the transaction, 0 otherwise. | |
de1b7941 | 557 | * The function can free jh and bh. |
470decc6 | 558 | * |
470decc6 | 559 | * This function is called with j_list_lock held. |
470decc6 | 560 | */ |
f7f4bccb | 561 | int __jbd2_journal_remove_checkpoint(struct journal_head *jh) |
470decc6 | 562 | { |
bf699327 | 563 | struct transaction_chp_stats_s *stats; |
470decc6 DK |
564 | transaction_t *transaction; |
565 | journal_t *journal; | |
566 | int ret = 0; | |
567 | ||
568 | JBUFFER_TRACE(jh, "entry"); | |
569 | ||
570 | if ((transaction = jh->b_cp_transaction) == NULL) { | |
571 | JBUFFER_TRACE(jh, "not on transaction"); | |
572 | goto out; | |
573 | } | |
574 | journal = transaction->t_journal; | |
575 | ||
de1b7941 | 576 | JBUFFER_TRACE(jh, "removing from transaction"); |
470decc6 DK |
577 | __buffer_unlink(jh); |
578 | jh->b_cp_transaction = NULL; | |
de1b7941 | 579 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
580 | |
581 | if (transaction->t_checkpoint_list != NULL || | |
582 | transaction->t_checkpoint_io_list != NULL) | |
583 | goto out; | |
470decc6 DK |
584 | |
585 | /* | |
586 | * There is one special case to worry about: if we have just pulled the | |
f5a7a6b0 JK |
587 | * buffer off a running or committing transaction's checkpoing list, |
588 | * then even if the checkpoint list is empty, the transaction obviously | |
589 | * cannot be dropped! | |
470decc6 | 590 | * |
f5a7a6b0 | 591 | * The locking here around t_state is a bit sleazy. |
f7f4bccb | 592 | * See the comment at the end of jbd2_journal_commit_transaction(). |
470decc6 | 593 | */ |
de1b7941 | 594 | if (transaction->t_state != T_FINISHED) |
470decc6 | 595 | goto out; |
470decc6 DK |
596 | |
597 | /* OK, that was the last buffer for the transaction: we can now | |
598 | safely remove this transaction from the log */ | |
bf699327 TT |
599 | stats = &transaction->t_chp_stats; |
600 | if (stats->cs_chp_time) | |
601 | stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time, | |
602 | jiffies); | |
603 | trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev, | |
604 | transaction->t_tid, stats); | |
470decc6 | 605 | |
f7f4bccb | 606 | __jbd2_journal_drop_transaction(journal, transaction); |
0c2022ec | 607 | jbd2_journal_free_transaction(transaction); |
470decc6 DK |
608 | ret = 1; |
609 | out: | |
470decc6 DK |
610 | return ret; |
611 | } | |
612 | ||
613 | /* | |
614 | * journal_insert_checkpoint: put a committed buffer onto a checkpoint | |
615 | * list so that we know when it is safe to clean the transaction out of | |
616 | * the log. | |
617 | * | |
618 | * Called with the journal locked. | |
619 | * Called with j_list_lock held. | |
620 | */ | |
f7f4bccb | 621 | void __jbd2_journal_insert_checkpoint(struct journal_head *jh, |
470decc6 DK |
622 | transaction_t *transaction) |
623 | { | |
624 | JBUFFER_TRACE(jh, "entry"); | |
625 | J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh))); | |
626 | J_ASSERT_JH(jh, jh->b_cp_transaction == NULL); | |
627 | ||
de1b7941 JK |
628 | /* Get reference for checkpointing transaction */ |
629 | jbd2_journal_grab_journal_head(jh2bh(jh)); | |
470decc6 DK |
630 | jh->b_cp_transaction = transaction; |
631 | ||
632 | if (!transaction->t_checkpoint_list) { | |
633 | jh->b_cpnext = jh->b_cpprev = jh; | |
634 | } else { | |
635 | jh->b_cpnext = transaction->t_checkpoint_list; | |
636 | jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev; | |
637 | jh->b_cpprev->b_cpnext = jh; | |
638 | jh->b_cpnext->b_cpprev = jh; | |
639 | } | |
640 | transaction->t_checkpoint_list = jh; | |
641 | } | |
642 | ||
643 | /* | |
644 | * We've finished with this transaction structure: adios... | |
645 | * | |
646 | * The transaction must have no links except for the checkpoint by this | |
647 | * point. | |
648 | * | |
649 | * Called with the journal locked. | |
650 | * Called with j_list_lock held. | |
651 | */ | |
652 | ||
f7f4bccb | 653 | void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
654 | { |
655 | assert_spin_locked(&journal->j_list_lock); | |
656 | if (transaction->t_cpnext) { | |
657 | transaction->t_cpnext->t_cpprev = transaction->t_cpprev; | |
658 | transaction->t_cpprev->t_cpnext = transaction->t_cpnext; | |
659 | if (journal->j_checkpoint_transactions == transaction) | |
660 | journal->j_checkpoint_transactions = | |
661 | transaction->t_cpnext; | |
662 | if (journal->j_checkpoint_transactions == transaction) | |
663 | journal->j_checkpoint_transactions = NULL; | |
664 | } | |
665 | ||
666 | J_ASSERT(transaction->t_state == T_FINISHED); | |
667 | J_ASSERT(transaction->t_buffers == NULL); | |
470decc6 | 668 | J_ASSERT(transaction->t_forget == NULL); |
470decc6 | 669 | J_ASSERT(transaction->t_shadow_list == NULL); |
470decc6 DK |
670 | J_ASSERT(transaction->t_checkpoint_list == NULL); |
671 | J_ASSERT(transaction->t_checkpoint_io_list == NULL); | |
a51dca9c | 672 | J_ASSERT(atomic_read(&transaction->t_updates) == 0); |
470decc6 DK |
673 | J_ASSERT(journal->j_committing_transaction != transaction); |
674 | J_ASSERT(journal->j_running_transaction != transaction); | |
675 | ||
2201c590 SA |
676 | trace_jbd2_drop_transaction(journal, transaction); |
677 | ||
470decc6 | 678 | jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid); |
470decc6 | 679 | } |