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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 | ||
4ba3fcdd ZY |
82 | /* |
83 | * Check a checkpoint buffer could be release or not. | |
84 | * | |
85 | * Requires j_list_lock | |
86 | */ | |
87 | static inline bool __cp_buffer_busy(struct journal_head *jh) | |
88 | { | |
89 | struct buffer_head *bh = jh2bh(jh); | |
90 | ||
91 | return (jh->b_transaction || buffer_locked(bh) || buffer_dirty(bh)); | |
92 | } | |
93 | ||
470decc6 | 94 | /* |
f7f4bccb | 95 | * __jbd2_log_wait_for_space: wait until there is space in the journal. |
470decc6 DK |
96 | * |
97 | * Called under j-state_lock *only*. It will be unlocked if we have to wait | |
98 | * for a checkpoint to free up some space in the log. | |
99 | */ | |
f7f4bccb | 100 | void __jbd2_log_wait_for_space(journal_t *journal) |
05d5233d TT |
101 | __acquires(&journal->j_state_lock) |
102 | __releases(&journal->j_state_lock) | |
470decc6 | 103 | { |
8c3f25d8 | 104 | int nblocks, space_left; |
a931da6a | 105 | /* assert_spin_locked(&journal->j_state_lock); */ |
470decc6 | 106 | |
77444ac4 | 107 | nblocks = journal->j_max_transaction_buffers; |
76c39904 | 108 | while (jbd2_log_space_left(journal) < nblocks) { |
a931da6a | 109 | write_unlock(&journal->j_state_lock); |
53cf9784 | 110 | mutex_lock_io(&journal->j_checkpoint_mutex); |
470decc6 DK |
111 | |
112 | /* | |
113 | * Test again, another process may have checkpointed while we | |
23f8b79e | 114 | * were waiting for the checkpoint lock. If there are no |
8c3f25d8 TT |
115 | * transactions ready to be checkpointed, try to recover |
116 | * journal space by calling cleanup_journal_tail(), and if | |
117 | * that doesn't work, by waiting for the currently committing | |
118 | * transaction to complete. If there is absolutely no way | |
119 | * to make progress, this is either a BUG or corrupted | |
120 | * filesystem, so abort the journal and leave a stack | |
121 | * trace for forensic evidence. | |
470decc6 | 122 | */ |
a931da6a | 123 | write_lock(&journal->j_state_lock); |
1245799f DM |
124 | if (journal->j_flags & JBD2_ABORT) { |
125 | mutex_unlock(&journal->j_checkpoint_mutex); | |
126 | return; | |
127 | } | |
23f8b79e | 128 | spin_lock(&journal->j_list_lock); |
76c39904 | 129 | space_left = jbd2_log_space_left(journal); |
8c3f25d8 | 130 | if (space_left < nblocks) { |
23f8b79e | 131 | int chkpt = journal->j_checkpoint_transactions != NULL; |
8c3f25d8 | 132 | tid_t tid = 0; |
23f8b79e | 133 | |
8c3f25d8 TT |
134 | if (journal->j_committing_transaction) |
135 | tid = journal->j_committing_transaction->t_tid; | |
23f8b79e | 136 | spin_unlock(&journal->j_list_lock); |
a931da6a | 137 | write_unlock(&journal->j_state_lock); |
23f8b79e DG |
138 | if (chkpt) { |
139 | jbd2_log_do_checkpoint(journal); | |
8c3f25d8 TT |
140 | } else if (jbd2_cleanup_journal_tail(journal) == 0) { |
141 | /* We were able to recover space; yay! */ | |
142 | ; | |
143 | } else if (tid) { | |
0ef54180 PG |
144 | /* |
145 | * jbd2_journal_commit_transaction() may want | |
146 | * to take the checkpoint_mutex if JBD2_FLUSHED | |
147 | * is set. So we need to temporarily drop it. | |
148 | */ | |
149 | mutex_unlock(&journal->j_checkpoint_mutex); | |
8c3f25d8 | 150 | jbd2_log_wait_commit(journal, tid); |
0ef54180 PG |
151 | write_lock(&journal->j_state_lock); |
152 | continue; | |
23f8b79e | 153 | } else { |
8c3f25d8 TT |
154 | printk(KERN_ERR "%s: needed %d blocks and " |
155 | "only had %d space available\n", | |
156 | __func__, nblocks, space_left); | |
157 | printk(KERN_ERR "%s: no way to get more " | |
158 | "journal space in %s\n", __func__, | |
159 | journal->j_devname); | |
160 | WARN_ON(1); | |
51f57b01 | 161 | jbd2_journal_abort(journal, -EIO); |
23f8b79e | 162 | } |
a931da6a | 163 | write_lock(&journal->j_state_lock); |
23f8b79e DG |
164 | } else { |
165 | spin_unlock(&journal->j_list_lock); | |
470decc6 DK |
166 | } |
167 | mutex_unlock(&journal->j_checkpoint_mutex); | |
168 | } | |
169 | } | |
170 | ||
470decc6 | 171 | static void |
1a0d3786 | 172 | __flush_batch(journal_t *journal, int *batch_count) |
470decc6 DK |
173 | { |
174 | int i; | |
d3ad8434 | 175 | struct blk_plug plug; |
470decc6 | 176 | |
d3ad8434 | 177 | blk_start_plug(&plug); |
9cb569d6 | 178 | for (i = 0; i < *batch_count; i++) |
70fd7614 | 179 | write_dirty_buffer(journal->j_chkpt_bhs[i], REQ_SYNC); |
d3ad8434 | 180 | blk_finish_plug(&plug); |
9cb569d6 | 181 | |
470decc6 | 182 | for (i = 0; i < *batch_count; i++) { |
1a0d3786 | 183 | struct buffer_head *bh = journal->j_chkpt_bhs[i]; |
470decc6 DK |
184 | BUFFER_TRACE(bh, "brelse"); |
185 | __brelse(bh); | |
186 | } | |
187 | *batch_count = 0; | |
188 | } | |
189 | ||
470decc6 DK |
190 | /* |
191 | * Perform an actual checkpoint. We take the first transaction on the | |
192 | * list of transactions to be checkpointed and send all its buffers | |
193 | * to disk. We submit larger chunks of data at once. | |
194 | * | |
195 | * The journal should be locked before calling this function. | |
44519faf | 196 | * Called with j_checkpoint_mutex held. |
470decc6 | 197 | */ |
f7f4bccb | 198 | int jbd2_log_do_checkpoint(journal_t *journal) |
470decc6 | 199 | { |
be1158cc TT |
200 | struct journal_head *jh; |
201 | struct buffer_head *bh; | |
202 | transaction_t *transaction; | |
203 | tid_t this_tid; | |
dc6e8d66 | 204 | int result, batch_count = 0; |
470decc6 DK |
205 | |
206 | jbd_debug(1, "Start checkpoint\n"); | |
207 | ||
208 | /* | |
209 | * First thing: if there are any transactions in the log which | |
210 | * don't need checkpointing, just eliminate them from the | |
211 | * journal straight away. | |
212 | */ | |
f7f4bccb | 213 | result = jbd2_cleanup_journal_tail(journal); |
879c5e6b | 214 | trace_jbd2_checkpoint(journal, result); |
470decc6 DK |
215 | jbd_debug(1, "cleanup_journal_tail returned %d\n", result); |
216 | if (result <= 0) | |
217 | return result; | |
218 | ||
219 | /* | |
220 | * OK, we need to start writing disk blocks. Take one transaction | |
221 | * and write it. | |
222 | */ | |
223 | spin_lock(&journal->j_list_lock); | |
224 | if (!journal->j_checkpoint_transactions) | |
225 | goto out; | |
226 | transaction = journal->j_checkpoint_transactions; | |
8e85fb3f JL |
227 | if (transaction->t_chp_stats.cs_chp_time == 0) |
228 | transaction->t_chp_stats.cs_chp_time = jiffies; | |
470decc6 DK |
229 | this_tid = transaction->t_tid; |
230 | restart: | |
231 | /* | |
232 | * If someone cleaned up this transaction while we slept, we're | |
233 | * done (maybe it's a new transaction, but it fell at the same | |
234 | * address). | |
235 | */ | |
be1158cc TT |
236 | if (journal->j_checkpoint_transactions != transaction || |
237 | transaction->t_tid != this_tid) | |
238 | goto out; | |
470decc6 | 239 | |
be1158cc TT |
240 | /* checkpoint all of the transaction's buffers */ |
241 | while (transaction->t_checkpoint_list) { | |
242 | jh = transaction->t_checkpoint_list; | |
243 | bh = jh2bh(jh); | |
244 | ||
245 | if (buffer_locked(bh)) { | |
be1158cc | 246 | get_bh(bh); |
ccd3c437 | 247 | spin_unlock(&journal->j_list_lock); |
be1158cc TT |
248 | wait_on_buffer(bh); |
249 | /* the journal_head may have gone by now */ | |
250 | BUFFER_TRACE(bh, "brelse"); | |
251 | __brelse(bh); | |
252 | goto retry; | |
470decc6 | 253 | } |
be1158cc TT |
254 | if (jh->b_transaction != NULL) { |
255 | transaction_t *t = jh->b_transaction; | |
256 | tid_t tid = t->t_tid; | |
470decc6 | 257 | |
be1158cc TT |
258 | transaction->t_chp_stats.cs_forced_to_close++; |
259 | spin_unlock(&journal->j_list_lock); | |
260 | if (unlikely(journal->j_flags & JBD2_UNMOUNT)) | |
261 | /* | |
262 | * The journal thread is dead; so | |
263 | * starting and waiting for a commit | |
264 | * to finish will cause us to wait for | |
265 | * a _very_ long time. | |
266 | */ | |
267 | printk(KERN_ERR | |
268 | "JBD2: %s: Waiting for Godot: block %llu\n", | |
269 | journal->j_devname, (unsigned long long) bh->b_blocknr); | |
270 | ||
53cf9784 XW |
271 | if (batch_count) |
272 | __flush_batch(journal, &batch_count); | |
be1158cc | 273 | jbd2_log_start_commit(journal, tid); |
53cf9784 XW |
274 | /* |
275 | * jbd2_journal_commit_transaction() may want | |
276 | * to take the checkpoint_mutex if JBD2_FLUSHED | |
277 | * is set, jbd2_update_log_tail() called by | |
278 | * jbd2_journal_commit_transaction() may also take | |
279 | * checkpoint_mutex. So we need to temporarily | |
280 | * drop it. | |
281 | */ | |
282 | mutex_unlock(&journal->j_checkpoint_mutex); | |
be1158cc | 283 | jbd2_log_wait_commit(journal, tid); |
53cf9784 XW |
284 | mutex_lock_io(&journal->j_checkpoint_mutex); |
285 | spin_lock(&journal->j_list_lock); | |
286 | goto restart; | |
be1158cc TT |
287 | } |
288 | if (!buffer_dirty(bh)) { | |
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 | 338 | if (buffer_locked(bh)) { |
dc6e8d66 | 339 | get_bh(bh); |
ccd3c437 | 340 | spin_unlock(&journal->j_list_lock); |
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 | } | |
88fe1acb TT |
348 | |
349 | /* | |
350 | * Now in whatever state the buffer currently is, we | |
351 | * know that it has been written out and so we can | |
352 | * drop it from the list | |
353 | */ | |
dc6e8d66 TT |
354 | if (__jbd2_journal_remove_checkpoint(jh)) |
355 | break; | |
88fe1acb | 356 | } |
470decc6 DK |
357 | out: |
358 | spin_unlock(&journal->j_list_lock); | |
214eb5a4 | 359 | result = jbd2_cleanup_journal_tail(journal); |
44519faf HK |
360 | |
361 | return (result < 0) ? result : 0; | |
470decc6 DK |
362 | } |
363 | ||
364 | /* | |
365 | * Check the list of checkpoint transactions for the journal to see if | |
366 | * we have already got rid of any since the last update of the log tail | |
367 | * in the journal superblock. If so, we can instantly roll the | |
368 | * superblock forward to remove those transactions from the log. | |
369 | * | |
370 | * Return <0 on error, 0 on success, 1 if there was nothing to clean up. | |
371 | * | |
372 | * Called with the journal lock held. | |
373 | * | |
374 | * This is the only part of the journaling code which really needs to be | |
375 | * aware of transaction aborts. Checkpointing involves writing to the | |
376 | * main filesystem area rather than to the journal, so it can proceed | |
44519faf HK |
377 | * even in abort state, but we must not update the super block if |
378 | * checkpointing may have failed. Otherwise, we would lose some metadata | |
379 | * buffers which should be written-back to the filesystem. | |
470decc6 DK |
380 | */ |
381 | ||
f7f4bccb | 382 | int jbd2_cleanup_journal_tail(journal_t *journal) |
470decc6 | 383 | { |
470decc6 | 384 | tid_t first_tid; |
79feb521 | 385 | unsigned long blocknr; |
470decc6 | 386 | |
44519faf | 387 | if (is_journal_aborted(journal)) |
6f6a6fda | 388 | return -EIO; |
44519faf | 389 | |
79feb521 | 390 | if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr)) |
470decc6 | 391 | return 1; |
79feb521 | 392 | J_ASSERT(blocknr != 0); |
cc3e1bea TT |
393 | |
394 | /* | |
79feb521 JK |
395 | * We need to make sure that any blocks that were recently written out |
396 | * --- perhaps by jbd2_log_do_checkpoint() --- are flushed out before | |
397 | * we drop the transactions from the journal. It's unlikely this will | |
398 | * be necessary, especially with an appropriately sized journal, but we | |
399 | * need this to guarantee correctness. Fortunately | |
400 | * jbd2_cleanup_journal_tail() doesn't get called all that often. | |
cc3e1bea | 401 | */ |
79feb521 | 402 | if (journal->j_flags & JBD2_BARRIER) |
c6bf3f0e | 403 | blkdev_issue_flush(journal->j_fs_dev); |
79feb521 | 404 | |
6f6a6fda | 405 | return __jbd2_update_log_tail(journal, first_tid, blocknr); |
470decc6 DK |
406 | } |
407 | ||
408 | ||
409 | /* Checkpoint list management */ | |
410 | ||
411 | /* | |
412 | * journal_clean_one_cp_list | |
413 | * | |
de1b7941 | 414 | * Find all the written-back checkpoint buffers in the given list and |
841df7df | 415 | * release them. If 'destroy' is set, clean all buffers unconditionally. |
470decc6 | 416 | * |
470decc6 | 417 | * Called with j_list_lock held. |
50849db3 | 418 | * Returns 1 if we freed the transaction, 0 otherwise. |
470decc6 | 419 | */ |
841df7df | 420 | static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy) |
470decc6 DK |
421 | { |
422 | struct journal_head *last_jh; | |
423 | struct journal_head *next_jh = jh; | |
470decc6 | 424 | |
470decc6 DK |
425 | if (!jh) |
426 | return 0; | |
427 | ||
428 | last_jh = jh->b_cpprev; | |
429 | do { | |
430 | jh = next_jh; | |
431 | next_jh = jh->b_cpnext; | |
dbf2bab7 ZY |
432 | |
433 | if (!destroy && __cp_buffer_busy(jh)) | |
33d14975 | 434 | return 0; |
dbf2bab7 ZY |
435 | |
436 | if (__jbd2_journal_remove_checkpoint(jh)) | |
50849db3 | 437 | return 1; |
470decc6 DK |
438 | /* |
439 | * This function only frees up some memory | |
440 | * if possible so we dont have an obligation | |
441 | * to finish processing. Bail out if preemption | |
442 | * requested: | |
443 | */ | |
444 | if (need_resched()) | |
33d14975 | 445 | return 0; |
470decc6 DK |
446 | } while (jh != last_jh); |
447 | ||
33d14975 | 448 | return 0; |
470decc6 DK |
449 | } |
450 | ||
4ba3fcdd ZY |
451 | /* |
452 | * journal_shrink_one_cp_list | |
453 | * | |
454 | * Find 'nr_to_scan' written-back checkpoint buffers in the given list | |
455 | * and try to release them. If the whole transaction is released, set | |
456 | * the 'released' parameter. Return the number of released checkpointed | |
457 | * buffers. | |
458 | * | |
459 | * Called with j_list_lock held. | |
460 | */ | |
461 | static unsigned long journal_shrink_one_cp_list(struct journal_head *jh, | |
462 | unsigned long *nr_to_scan, | |
463 | bool *released) | |
464 | { | |
465 | struct journal_head *last_jh; | |
466 | struct journal_head *next_jh = jh; | |
467 | unsigned long nr_freed = 0; | |
468 | int ret; | |
469 | ||
470 | if (!jh || *nr_to_scan == 0) | |
471 | return 0; | |
472 | ||
473 | last_jh = jh->b_cpprev; | |
474 | do { | |
475 | jh = next_jh; | |
476 | next_jh = jh->b_cpnext; | |
477 | ||
478 | (*nr_to_scan)--; | |
479 | if (__cp_buffer_busy(jh)) | |
480 | continue; | |
481 | ||
482 | nr_freed++; | |
483 | ret = __jbd2_journal_remove_checkpoint(jh); | |
484 | if (ret) { | |
485 | *released = true; | |
486 | break; | |
487 | } | |
488 | ||
489 | if (need_resched()) | |
490 | break; | |
491 | } while (jh != last_jh && *nr_to_scan); | |
492 | ||
493 | return nr_freed; | |
494 | } | |
495 | ||
496 | /* | |
497 | * jbd2_journal_shrink_checkpoint_list | |
498 | * | |
499 | * Find 'nr_to_scan' written-back checkpoint buffers in the journal | |
500 | * and try to release them. Return the number of released checkpointed | |
501 | * buffers. | |
502 | * | |
503 | * Called with j_list_lock held. | |
504 | */ | |
505 | unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal, | |
506 | unsigned long *nr_to_scan) | |
507 | { | |
508 | transaction_t *transaction, *last_transaction, *next_transaction; | |
509 | bool released; | |
510 | tid_t first_tid = 0, last_tid = 0, next_tid = 0; | |
511 | tid_t tid = 0; | |
512 | unsigned long nr_freed = 0; | |
513 | unsigned long nr_scanned = *nr_to_scan; | |
514 | ||
515 | again: | |
516 | spin_lock(&journal->j_list_lock); | |
517 | if (!journal->j_checkpoint_transactions) { | |
518 | spin_unlock(&journal->j_list_lock); | |
519 | goto out; | |
520 | } | |
521 | ||
522 | /* | |
523 | * Get next shrink transaction, resume previous scan or start | |
524 | * over again. If some others do checkpoint and drop transaction | |
525 | * from the checkpoint list, we ignore saved j_shrink_transaction | |
526 | * and start over unconditionally. | |
527 | */ | |
528 | if (journal->j_shrink_transaction) | |
529 | transaction = journal->j_shrink_transaction; | |
530 | else | |
531 | transaction = journal->j_checkpoint_transactions; | |
532 | ||
533 | if (!first_tid) | |
534 | first_tid = transaction->t_tid; | |
535 | last_transaction = journal->j_checkpoint_transactions->t_cpprev; | |
536 | next_transaction = transaction; | |
537 | last_tid = last_transaction->t_tid; | |
538 | do { | |
539 | transaction = next_transaction; | |
540 | next_transaction = transaction->t_cpnext; | |
541 | tid = transaction->t_tid; | |
542 | released = false; | |
543 | ||
544 | nr_freed += journal_shrink_one_cp_list(transaction->t_checkpoint_list, | |
545 | nr_to_scan, &released); | |
546 | if (*nr_to_scan == 0) | |
547 | break; | |
548 | if (need_resched() || spin_needbreak(&journal->j_list_lock)) | |
549 | break; | |
550 | if (released) | |
551 | continue; | |
552 | ||
553 | nr_freed += journal_shrink_one_cp_list(transaction->t_checkpoint_io_list, | |
554 | nr_to_scan, &released); | |
555 | if (*nr_to_scan == 0) | |
556 | break; | |
557 | if (need_resched() || spin_needbreak(&journal->j_list_lock)) | |
558 | break; | |
559 | } while (transaction != last_transaction); | |
560 | ||
561 | if (transaction != last_transaction) { | |
562 | journal->j_shrink_transaction = next_transaction; | |
563 | next_tid = next_transaction->t_tid; | |
564 | } else { | |
565 | journal->j_shrink_transaction = NULL; | |
566 | next_tid = 0; | |
567 | } | |
568 | ||
569 | spin_unlock(&journal->j_list_lock); | |
570 | cond_resched(); | |
571 | ||
572 | if (*nr_to_scan && next_tid) | |
573 | goto again; | |
574 | out: | |
575 | nr_scanned -= *nr_to_scan; | |
576 | trace_jbd2_shrink_checkpoint_list(journal, first_tid, tid, last_tid, | |
577 | nr_freed, nr_scanned, next_tid); | |
578 | ||
579 | return nr_freed; | |
580 | } | |
581 | ||
470decc6 DK |
582 | /* |
583 | * journal_clean_checkpoint_list | |
584 | * | |
585 | * Find all the written-back checkpoint buffers in the journal and release them. | |
841df7df | 586 | * If 'destroy' is set, release all buffers unconditionally. |
470decc6 | 587 | * |
470decc6 | 588 | * Called with j_list_lock held. |
470decc6 | 589 | */ |
841df7df | 590 | void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy) |
470decc6 DK |
591 | { |
592 | transaction_t *transaction, *last_transaction, *next_transaction; | |
cc97f1a7 | 593 | int ret; |
470decc6 DK |
594 | |
595 | transaction = journal->j_checkpoint_transactions; | |
596 | if (!transaction) | |
50849db3 | 597 | return; |
470decc6 DK |
598 | |
599 | last_transaction = transaction->t_cpprev; | |
600 | next_transaction = transaction; | |
601 | do { | |
602 | transaction = next_transaction; | |
603 | next_transaction = transaction->t_cpnext; | |
841df7df JK |
604 | ret = journal_clean_one_cp_list(transaction->t_checkpoint_list, |
605 | destroy); | |
470decc6 DK |
606 | /* |
607 | * This function only frees up some memory if possible so we | |
608 | * dont have an obligation to finish processing. Bail out if | |
609 | * preemption requested: | |
610 | */ | |
50849db3 JK |
611 | if (need_resched()) |
612 | return; | |
613 | if (ret) | |
470decc6 DK |
614 | continue; |
615 | /* | |
616 | * It is essential that we are as careful as in the case of | |
617 | * t_checkpoint_list with removing the buffer from the list as | |
618 | * we can possibly see not yet submitted buffers on io_list | |
619 | */ | |
50849db3 | 620 | ret = journal_clean_one_cp_list(transaction-> |
841df7df | 621 | t_checkpoint_io_list, destroy); |
50849db3 JK |
622 | if (need_resched()) |
623 | return; | |
624 | /* | |
625 | * Stop scanning if we couldn't free the transaction. This | |
626 | * avoids pointless scanning of transactions which still | |
627 | * weren't checkpointed. | |
628 | */ | |
629 | if (!ret) | |
630 | return; | |
470decc6 | 631 | } while (transaction != last_transaction); |
470decc6 DK |
632 | } |
633 | ||
841df7df JK |
634 | /* |
635 | * Remove buffers from all checkpoint lists as journal is aborted and we just | |
636 | * need to free memory | |
637 | */ | |
638 | void jbd2_journal_destroy_checkpoint(journal_t *journal) | |
639 | { | |
640 | /* | |
641 | * We loop because __jbd2_journal_clean_checkpoint_list() may abort | |
642 | * early due to a need of rescheduling. | |
643 | */ | |
644 | while (1) { | |
645 | spin_lock(&journal->j_list_lock); | |
646 | if (!journal->j_checkpoint_transactions) { | |
647 | spin_unlock(&journal->j_list_lock); | |
648 | break; | |
649 | } | |
650 | __jbd2_journal_clean_checkpoint_list(journal, true); | |
651 | spin_unlock(&journal->j_list_lock); | |
652 | cond_resched(); | |
653 | } | |
654 | } | |
655 | ||
470decc6 DK |
656 | /* |
657 | * journal_remove_checkpoint: called after a buffer has been committed | |
658 | * to disk (either by being write-back flushed to disk, or being | |
659 | * committed to the log). | |
660 | * | |
661 | * We cannot safely clean a transaction out of the log until all of the | |
662 | * buffer updates committed in that transaction have safely been stored | |
663 | * elsewhere on disk. To achieve this, all of the buffers in a | |
664 | * transaction need to be maintained on the transaction's checkpoint | |
665 | * lists until they have been rewritten, at which point this function is | |
666 | * called to remove the buffer from the existing transaction's | |
667 | * checkpoint lists. | |
668 | * | |
669 | * The function returns 1 if it frees the transaction, 0 otherwise. | |
de1b7941 | 670 | * The function can free jh and bh. |
470decc6 | 671 | * |
470decc6 | 672 | * This function is called with j_list_lock held. |
470decc6 | 673 | */ |
f7f4bccb | 674 | int __jbd2_journal_remove_checkpoint(struct journal_head *jh) |
470decc6 | 675 | { |
bf699327 | 676 | struct transaction_chp_stats_s *stats; |
470decc6 DK |
677 | transaction_t *transaction; |
678 | journal_t *journal; | |
fcf37549 | 679 | struct buffer_head *bh = jh2bh(jh); |
470decc6 DK |
680 | |
681 | JBUFFER_TRACE(jh, "entry"); | |
682 | ||
1866cba8 ZY |
683 | transaction = jh->b_cp_transaction; |
684 | if (!transaction) { | |
470decc6 | 685 | JBUFFER_TRACE(jh, "not on transaction"); |
1866cba8 | 686 | return 0; |
470decc6 DK |
687 | } |
688 | journal = transaction->t_journal; | |
689 | ||
de1b7941 | 690 | JBUFFER_TRACE(jh, "removing from transaction"); |
fcf37549 ZY |
691 | |
692 | /* | |
693 | * If we have failed to write the buffer out to disk, the filesystem | |
694 | * may become inconsistent. We cannot abort the journal here since | |
695 | * we hold j_list_lock and we have to be careful about races with | |
696 | * jbd2_journal_destroy(). So mark the writeback IO error in the | |
697 | * journal here and we abort the journal later from a better context. | |
698 | */ | |
699 | if (buffer_write_io_error(bh)) | |
700 | set_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags); | |
701 | ||
470decc6 DK |
702 | __buffer_unlink(jh); |
703 | jh->b_cp_transaction = NULL; | |
0705e8d1 | 704 | percpu_counter_dec(&journal->j_checkpoint_jh_count); |
de1b7941 | 705 | jbd2_journal_put_journal_head(jh); |
470decc6 | 706 | |
1866cba8 ZY |
707 | /* Is this transaction empty? */ |
708 | if (transaction->t_checkpoint_list || transaction->t_checkpoint_io_list) | |
709 | return 0; | |
470decc6 DK |
710 | |
711 | /* | |
712 | * There is one special case to worry about: if we have just pulled the | |
f5a7a6b0 JK |
713 | * buffer off a running or committing transaction's checkpoing list, |
714 | * then even if the checkpoint list is empty, the transaction obviously | |
715 | * cannot be dropped! | |
470decc6 | 716 | * |
f5a7a6b0 | 717 | * The locking here around t_state is a bit sleazy. |
f7f4bccb | 718 | * See the comment at the end of jbd2_journal_commit_transaction(). |
470decc6 | 719 | */ |
de1b7941 | 720 | if (transaction->t_state != T_FINISHED) |
1866cba8 | 721 | return 0; |
470decc6 | 722 | |
1866cba8 ZY |
723 | /* |
724 | * OK, that was the last buffer for the transaction, we can now | |
725 | * safely remove this transaction from the log. | |
726 | */ | |
bf699327 TT |
727 | stats = &transaction->t_chp_stats; |
728 | if (stats->cs_chp_time) | |
729 | stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time, | |
730 | jiffies); | |
731 | trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev, | |
732 | transaction->t_tid, stats); | |
470decc6 | 733 | |
f7f4bccb | 734 | __jbd2_journal_drop_transaction(journal, transaction); |
0c2022ec | 735 | jbd2_journal_free_transaction(transaction); |
1866cba8 | 736 | return 1; |
470decc6 DK |
737 | } |
738 | ||
739 | /* | |
740 | * journal_insert_checkpoint: put a committed buffer onto a checkpoint | |
741 | * list so that we know when it is safe to clean the transaction out of | |
742 | * the log. | |
743 | * | |
744 | * Called with the journal locked. | |
745 | * Called with j_list_lock held. | |
746 | */ | |
f7f4bccb | 747 | void __jbd2_journal_insert_checkpoint(struct journal_head *jh, |
470decc6 DK |
748 | transaction_t *transaction) |
749 | { | |
750 | JBUFFER_TRACE(jh, "entry"); | |
751 | J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh))); | |
752 | J_ASSERT_JH(jh, jh->b_cp_transaction == NULL); | |
753 | ||
de1b7941 JK |
754 | /* Get reference for checkpointing transaction */ |
755 | jbd2_journal_grab_journal_head(jh2bh(jh)); | |
470decc6 DK |
756 | jh->b_cp_transaction = transaction; |
757 | ||
758 | if (!transaction->t_checkpoint_list) { | |
759 | jh->b_cpnext = jh->b_cpprev = jh; | |
760 | } else { | |
761 | jh->b_cpnext = transaction->t_checkpoint_list; | |
762 | jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev; | |
763 | jh->b_cpprev->b_cpnext = jh; | |
764 | jh->b_cpnext->b_cpprev = jh; | |
765 | } | |
766 | transaction->t_checkpoint_list = jh; | |
0705e8d1 | 767 | percpu_counter_inc(&transaction->t_journal->j_checkpoint_jh_count); |
470decc6 DK |
768 | } |
769 | ||
770 | /* | |
771 | * We've finished with this transaction structure: adios... | |
772 | * | |
773 | * The transaction must have no links except for the checkpoint by this | |
774 | * point. | |
775 | * | |
776 | * Called with the journal locked. | |
777 | * Called with j_list_lock held. | |
778 | */ | |
779 | ||
f7f4bccb | 780 | void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
781 | { |
782 | assert_spin_locked(&journal->j_list_lock); | |
4ba3fcdd ZY |
783 | |
784 | journal->j_shrink_transaction = NULL; | |
470decc6 DK |
785 | if (transaction->t_cpnext) { |
786 | transaction->t_cpnext->t_cpprev = transaction->t_cpprev; | |
787 | transaction->t_cpprev->t_cpnext = transaction->t_cpnext; | |
788 | if (journal->j_checkpoint_transactions == transaction) | |
789 | journal->j_checkpoint_transactions = | |
790 | transaction->t_cpnext; | |
791 | if (journal->j_checkpoint_transactions == transaction) | |
792 | journal->j_checkpoint_transactions = NULL; | |
793 | } | |
794 | ||
795 | J_ASSERT(transaction->t_state == T_FINISHED); | |
796 | J_ASSERT(transaction->t_buffers == NULL); | |
470decc6 | 797 | J_ASSERT(transaction->t_forget == NULL); |
470decc6 | 798 | J_ASSERT(transaction->t_shadow_list == NULL); |
470decc6 DK |
799 | J_ASSERT(transaction->t_checkpoint_list == NULL); |
800 | J_ASSERT(transaction->t_checkpoint_io_list == NULL); | |
a51dca9c | 801 | J_ASSERT(atomic_read(&transaction->t_updates) == 0); |
470decc6 DK |
802 | J_ASSERT(journal->j_committing_transaction != transaction); |
803 | J_ASSERT(journal->j_running_transaction != transaction); | |
804 | ||
2201c590 SA |
805 | trace_jbd2_drop_transaction(journal, transaction); |
806 | ||
470decc6 | 807 | jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid); |
470decc6 | 808 | } |