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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 | |
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)) { |
de1b7941 JK |
99 | /* |
100 | * Get our reference so that bh cannot be freed before | |
101 | * we unlock it | |
102 | */ | |
103 | get_bh(bh); | |
470decc6 | 104 | JBUFFER_TRACE(jh, "remove from checkpoint list"); |
f7f4bccb | 105 | ret = __jbd2_journal_remove_checkpoint(jh) + 1; |
470decc6 DK |
106 | BUFFER_TRACE(bh, "release"); |
107 | __brelse(bh); | |
470decc6 DK |
108 | } |
109 | return ret; | |
110 | } | |
111 | ||
112 | /* | |
f7f4bccb | 113 | * __jbd2_log_wait_for_space: wait until there is space in the journal. |
470decc6 DK |
114 | * |
115 | * Called under j-state_lock *only*. It will be unlocked if we have to wait | |
116 | * for a checkpoint to free up some space in the log. | |
117 | */ | |
f7f4bccb | 118 | void __jbd2_log_wait_for_space(journal_t *journal) |
470decc6 | 119 | { |
8c3f25d8 | 120 | int nblocks, space_left; |
a931da6a | 121 | /* assert_spin_locked(&journal->j_state_lock); */ |
470decc6 | 122 | |
76c39904 JK |
123 | nblocks = jbd2_space_needed(journal); |
124 | while (jbd2_log_space_left(journal) < nblocks) { | |
f7f4bccb | 125 | if (journal->j_flags & JBD2_ABORT) |
470decc6 | 126 | return; |
a931da6a | 127 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
128 | mutex_lock(&journal->j_checkpoint_mutex); |
129 | ||
130 | /* | |
131 | * Test again, another process may have checkpointed while we | |
23f8b79e | 132 | * were waiting for the checkpoint lock. If there are no |
8c3f25d8 TT |
133 | * transactions ready to be checkpointed, try to recover |
134 | * journal space by calling cleanup_journal_tail(), and if | |
135 | * that doesn't work, by waiting for the currently committing | |
136 | * transaction to complete. If there is absolutely no way | |
137 | * to make progress, this is either a BUG or corrupted | |
138 | * filesystem, so abort the journal and leave a stack | |
139 | * trace for forensic evidence. | |
470decc6 | 140 | */ |
a931da6a | 141 | write_lock(&journal->j_state_lock); |
23f8b79e | 142 | spin_lock(&journal->j_list_lock); |
76c39904 JK |
143 | nblocks = jbd2_space_needed(journal); |
144 | space_left = jbd2_log_space_left(journal); | |
8c3f25d8 | 145 | if (space_left < nblocks) { |
23f8b79e | 146 | int chkpt = journal->j_checkpoint_transactions != NULL; |
8c3f25d8 | 147 | tid_t tid = 0; |
23f8b79e | 148 | |
8c3f25d8 TT |
149 | if (journal->j_committing_transaction) |
150 | tid = journal->j_committing_transaction->t_tid; | |
23f8b79e | 151 | spin_unlock(&journal->j_list_lock); |
a931da6a | 152 | write_unlock(&journal->j_state_lock); |
23f8b79e DG |
153 | if (chkpt) { |
154 | jbd2_log_do_checkpoint(journal); | |
8c3f25d8 TT |
155 | } else if (jbd2_cleanup_journal_tail(journal) == 0) { |
156 | /* We were able to recover space; yay! */ | |
157 | ; | |
158 | } else if (tid) { | |
0ef54180 PG |
159 | /* |
160 | * jbd2_journal_commit_transaction() may want | |
161 | * to take the checkpoint_mutex if JBD2_FLUSHED | |
162 | * is set. So we need to temporarily drop it. | |
163 | */ | |
164 | mutex_unlock(&journal->j_checkpoint_mutex); | |
8c3f25d8 | 165 | jbd2_log_wait_commit(journal, tid); |
0ef54180 PG |
166 | write_lock(&journal->j_state_lock); |
167 | continue; | |
23f8b79e | 168 | } else { |
8c3f25d8 TT |
169 | printk(KERN_ERR "%s: needed %d blocks and " |
170 | "only had %d space available\n", | |
171 | __func__, nblocks, space_left); | |
172 | printk(KERN_ERR "%s: no way to get more " | |
173 | "journal space in %s\n", __func__, | |
174 | journal->j_devname); | |
175 | WARN_ON(1); | |
23f8b79e DG |
176 | jbd2_journal_abort(journal, 0); |
177 | } | |
a931da6a | 178 | write_lock(&journal->j_state_lock); |
23f8b79e DG |
179 | } else { |
180 | spin_unlock(&journal->j_list_lock); | |
470decc6 DK |
181 | } |
182 | mutex_unlock(&journal->j_checkpoint_mutex); | |
183 | } | |
184 | } | |
185 | ||
470decc6 DK |
186 | /* |
187 | * Clean up transaction's list of buffers submitted for io. | |
188 | * We wait for any pending IO to complete and remove any clean | |
189 | * buffers. Note that we take the buffers in the opposite ordering | |
190 | * from the one in which they were submitted for IO. | |
191 | * | |
44519faf HK |
192 | * Return 0 on success, and return <0 if some buffers have failed |
193 | * to be written out. | |
194 | * | |
470decc6 DK |
195 | * Called with j_list_lock held. |
196 | */ | |
44519faf | 197 | static int __wait_cp_io(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
198 | { |
199 | struct journal_head *jh; | |
200 | struct buffer_head *bh; | |
201 | tid_t this_tid; | |
202 | int released = 0; | |
44519faf | 203 | int ret = 0; |
470decc6 DK |
204 | |
205 | this_tid = transaction->t_tid; | |
206 | restart: | |
207 | /* Did somebody clean up the transaction in the meanwhile? */ | |
208 | if (journal->j_checkpoint_transactions != transaction || | |
209 | transaction->t_tid != this_tid) | |
44519faf | 210 | return ret; |
470decc6 DK |
211 | while (!released && transaction->t_checkpoint_io_list) { |
212 | jh = transaction->t_checkpoint_io_list; | |
213 | bh = jh2bh(jh); | |
de1b7941 | 214 | get_bh(bh); |
470decc6 | 215 | if (buffer_locked(bh)) { |
470decc6 | 216 | spin_unlock(&journal->j_list_lock); |
470decc6 DK |
217 | wait_on_buffer(bh); |
218 | /* the journal_head may have gone by now */ | |
219 | BUFFER_TRACE(bh, "brelse"); | |
220 | __brelse(bh); | |
221 | spin_lock(&journal->j_list_lock); | |
222 | goto restart; | |
223 | } | |
44519faf HK |
224 | if (unlikely(buffer_write_io_error(bh))) |
225 | ret = -EIO; | |
226 | ||
470decc6 DK |
227 | /* |
228 | * Now in whatever state the buffer currently is, we know that | |
229 | * it has been written out and so we can drop it from the list | |
230 | */ | |
f7f4bccb | 231 | released = __jbd2_journal_remove_checkpoint(jh); |
470decc6 DK |
232 | __brelse(bh); |
233 | } | |
44519faf HK |
234 | |
235 | return ret; | |
470decc6 DK |
236 | } |
237 | ||
470decc6 | 238 | static void |
1a0d3786 | 239 | __flush_batch(journal_t *journal, int *batch_count) |
470decc6 DK |
240 | { |
241 | int i; | |
d3ad8434 | 242 | struct blk_plug plug; |
470decc6 | 243 | |
d3ad8434 | 244 | blk_start_plug(&plug); |
9cb569d6 | 245 | for (i = 0; i < *batch_count; i++) |
d3ad8434 TM |
246 | write_dirty_buffer(journal->j_chkpt_bhs[i], WRITE_SYNC); |
247 | blk_finish_plug(&plug); | |
9cb569d6 | 248 | |
470decc6 | 249 | for (i = 0; i < *batch_count; i++) { |
1a0d3786 | 250 | struct buffer_head *bh = journal->j_chkpt_bhs[i]; |
470decc6 DK |
251 | BUFFER_TRACE(bh, "brelse"); |
252 | __brelse(bh); | |
253 | } | |
254 | *batch_count = 0; | |
255 | } | |
256 | ||
257 | /* | |
258 | * Try to flush one buffer from the checkpoint list to disk. | |
259 | * | |
260 | * Return 1 if something happened which requires us to abort the current | |
44519faf HK |
261 | * scan of the checkpoint list. Return <0 if the buffer has failed to |
262 | * be written out. | |
470decc6 DK |
263 | * |
264 | * Called with j_list_lock held and drops it if 1 is returned | |
470decc6 DK |
265 | */ |
266 | static int __process_buffer(journal_t *journal, struct journal_head *jh, | |
1a0d3786 | 267 | int *batch_count, transaction_t *transaction) |
470decc6 DK |
268 | { |
269 | struct buffer_head *bh = jh2bh(jh); | |
270 | int ret = 0; | |
271 | ||
272 | if (buffer_locked(bh)) { | |
de1b7941 | 273 | get_bh(bh); |
470decc6 | 274 | spin_unlock(&journal->j_list_lock); |
470decc6 DK |
275 | wait_on_buffer(bh); |
276 | /* the journal_head may have gone by now */ | |
277 | BUFFER_TRACE(bh, "brelse"); | |
278 | __brelse(bh); | |
279 | ret = 1; | |
280 | } else if (jh->b_transaction != NULL) { | |
281 | transaction_t *t = jh->b_transaction; | |
282 | tid_t tid = t->t_tid; | |
283 | ||
8e85fb3f | 284 | transaction->t_chp_stats.cs_forced_to_close++; |
470decc6 | 285 | spin_unlock(&journal->j_list_lock); |
5c2178e7 TT |
286 | if (unlikely(journal->j_flags & JBD2_UNMOUNT)) |
287 | /* | |
288 | * The journal thread is dead; so starting and | |
289 | * waiting for a commit to finish will cause | |
290 | * us to wait for a _very_ long time. | |
291 | */ | |
292 | printk(KERN_ERR "JBD2: %s: " | |
293 | "Waiting for Godot: block %llu\n", | |
294 | journal->j_devname, | |
295 | (unsigned long long) bh->b_blocknr); | |
f7f4bccb MC |
296 | jbd2_log_start_commit(journal, tid); |
297 | jbd2_log_wait_commit(journal, tid); | |
470decc6 DK |
298 | ret = 1; |
299 | } else if (!buffer_dirty(bh)) { | |
44519faf HK |
300 | ret = 1; |
301 | if (unlikely(buffer_write_io_error(bh))) | |
302 | ret = -EIO; | |
de1b7941 | 303 | get_bh(bh); |
470decc6 | 304 | BUFFER_TRACE(bh, "remove from checkpoint"); |
f7f4bccb | 305 | __jbd2_journal_remove_checkpoint(jh); |
470decc6 | 306 | spin_unlock(&journal->j_list_lock); |
470decc6 | 307 | __brelse(bh); |
470decc6 DK |
308 | } else { |
309 | /* | |
310 | * Important: we are about to write the buffer, and | |
311 | * possibly block, while still holding the journal lock. | |
312 | * We cannot afford to let the transaction logic start | |
313 | * messing around with this buffer before we write it to | |
314 | * disk, as that would break recoverability. | |
315 | */ | |
316 | BUFFER_TRACE(bh, "queue"); | |
317 | get_bh(bh); | |
318 | J_ASSERT_BH(bh, !buffer_jwrite(bh)); | |
1a0d3786 | 319 | journal->j_chkpt_bhs[*batch_count] = bh; |
470decc6 | 320 | __buffer_relink_io(jh); |
8e85fb3f | 321 | transaction->t_chp_stats.cs_written++; |
470decc6 | 322 | (*batch_count)++; |
1a0d3786 | 323 | if (*batch_count == JBD2_NR_BATCH) { |
470decc6 | 324 | spin_unlock(&journal->j_list_lock); |
1a0d3786 | 325 | __flush_batch(journal, batch_count); |
470decc6 DK |
326 | ret = 1; |
327 | } | |
328 | } | |
329 | return ret; | |
330 | } | |
331 | ||
332 | /* | |
333 | * Perform an actual checkpoint. We take the first transaction on the | |
334 | * list of transactions to be checkpointed and send all its buffers | |
335 | * to disk. We submit larger chunks of data at once. | |
336 | * | |
337 | * The journal should be locked before calling this function. | |
44519faf | 338 | * Called with j_checkpoint_mutex held. |
470decc6 | 339 | */ |
f7f4bccb | 340 | int jbd2_log_do_checkpoint(journal_t *journal) |
470decc6 DK |
341 | { |
342 | transaction_t *transaction; | |
343 | tid_t this_tid; | |
344 | int result; | |
345 | ||
346 | jbd_debug(1, "Start checkpoint\n"); | |
347 | ||
348 | /* | |
349 | * First thing: if there are any transactions in the log which | |
350 | * don't need checkpointing, just eliminate them from the | |
351 | * journal straight away. | |
352 | */ | |
f7f4bccb | 353 | result = jbd2_cleanup_journal_tail(journal); |
879c5e6b | 354 | trace_jbd2_checkpoint(journal, result); |
470decc6 DK |
355 | jbd_debug(1, "cleanup_journal_tail returned %d\n", result); |
356 | if (result <= 0) | |
357 | return result; | |
358 | ||
359 | /* | |
360 | * OK, we need to start writing disk blocks. Take one transaction | |
361 | * and write it. | |
362 | */ | |
44519faf | 363 | result = 0; |
470decc6 DK |
364 | spin_lock(&journal->j_list_lock); |
365 | if (!journal->j_checkpoint_transactions) | |
366 | goto out; | |
367 | transaction = journal->j_checkpoint_transactions; | |
8e85fb3f JL |
368 | if (transaction->t_chp_stats.cs_chp_time == 0) |
369 | transaction->t_chp_stats.cs_chp_time = jiffies; | |
470decc6 DK |
370 | this_tid = transaction->t_tid; |
371 | restart: | |
372 | /* | |
373 | * If someone cleaned up this transaction while we slept, we're | |
374 | * done (maybe it's a new transaction, but it fell at the same | |
375 | * address). | |
376 | */ | |
377 | if (journal->j_checkpoint_transactions == transaction && | |
378 | transaction->t_tid == this_tid) { | |
379 | int batch_count = 0; | |
470decc6 | 380 | struct journal_head *jh; |
44519faf | 381 | int retry = 0, err; |
470decc6 DK |
382 | |
383 | while (!retry && transaction->t_checkpoint_list) { | |
470decc6 | 384 | jh = transaction->t_checkpoint_list; |
1a0d3786 | 385 | retry = __process_buffer(journal, jh, &batch_count, |
8e85fb3f | 386 | transaction); |
44519faf HK |
387 | if (retry < 0 && !result) |
388 | result = retry; | |
95c354fe NP |
389 | if (!retry && (need_resched() || |
390 | spin_needbreak(&journal->j_list_lock))) { | |
470decc6 DK |
391 | spin_unlock(&journal->j_list_lock); |
392 | retry = 1; | |
393 | break; | |
394 | } | |
395 | } | |
396 | ||
397 | if (batch_count) { | |
398 | if (!retry) { | |
399 | spin_unlock(&journal->j_list_lock); | |
400 | retry = 1; | |
401 | } | |
1a0d3786 | 402 | __flush_batch(journal, &batch_count); |
470decc6 DK |
403 | } |
404 | ||
405 | if (retry) { | |
406 | spin_lock(&journal->j_list_lock); | |
407 | goto restart; | |
408 | } | |
409 | /* | |
410 | * Now we have cleaned up the first transaction's checkpoint | |
411 | * list. Let's clean up the second one | |
412 | */ | |
44519faf HK |
413 | err = __wait_cp_io(journal, transaction); |
414 | if (!result) | |
415 | result = err; | |
470decc6 DK |
416 | } |
417 | out: | |
418 | spin_unlock(&journal->j_list_lock); | |
470decc6 | 419 | if (result < 0) |
44519faf HK |
420 | jbd2_journal_abort(journal, result); |
421 | else | |
422 | result = jbd2_cleanup_journal_tail(journal); | |
423 | ||
424 | return (result < 0) ? result : 0; | |
470decc6 DK |
425 | } |
426 | ||
427 | /* | |
428 | * Check the list of checkpoint transactions for the journal to see if | |
429 | * we have already got rid of any since the last update of the log tail | |
430 | * in the journal superblock. If so, we can instantly roll the | |
431 | * superblock forward to remove those transactions from the log. | |
432 | * | |
433 | * Return <0 on error, 0 on success, 1 if there was nothing to clean up. | |
434 | * | |
435 | * Called with the journal lock held. | |
436 | * | |
437 | * This is the only part of the journaling code which really needs to be | |
438 | * aware of transaction aborts. Checkpointing involves writing to the | |
439 | * main filesystem area rather than to the journal, so it can proceed | |
44519faf HK |
440 | * even in abort state, but we must not update the super block if |
441 | * checkpointing may have failed. Otherwise, we would lose some metadata | |
442 | * buffers which should be written-back to the filesystem. | |
470decc6 DK |
443 | */ |
444 | ||
f7f4bccb | 445 | int jbd2_cleanup_journal_tail(journal_t *journal) |
470decc6 | 446 | { |
470decc6 | 447 | tid_t first_tid; |
79feb521 | 448 | unsigned long blocknr; |
470decc6 | 449 | |
44519faf HK |
450 | if (is_journal_aborted(journal)) |
451 | return 1; | |
452 | ||
79feb521 | 453 | if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr)) |
470decc6 | 454 | return 1; |
79feb521 | 455 | J_ASSERT(blocknr != 0); |
cc3e1bea TT |
456 | |
457 | /* | |
79feb521 JK |
458 | * We need to make sure that any blocks that were recently written out |
459 | * --- perhaps by jbd2_log_do_checkpoint() --- are flushed out before | |
460 | * we drop the transactions from the journal. It's unlikely this will | |
461 | * be necessary, especially with an appropriately sized journal, but we | |
462 | * need this to guarantee correctness. Fortunately | |
463 | * jbd2_cleanup_journal_tail() doesn't get called all that often. | |
cc3e1bea | 464 | */ |
79feb521 | 465 | if (journal->j_flags & JBD2_BARRIER) |
dd3932ed | 466 | blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL); |
79feb521 JK |
467 | |
468 | __jbd2_update_log_tail(journal, first_tid, blocknr); | |
470decc6 DK |
469 | return 0; |
470 | } | |
471 | ||
472 | ||
473 | /* Checkpoint list management */ | |
474 | ||
475 | /* | |
476 | * journal_clean_one_cp_list | |
477 | * | |
de1b7941 JK |
478 | * Find all the written-back checkpoint buffers in the given list and |
479 | * release them. | |
470decc6 DK |
480 | * |
481 | * Called with the journal locked. | |
482 | * Called with j_list_lock held. | |
90802ed9 | 483 | * Returns number of buffers reaped (for debug) |
470decc6 DK |
484 | */ |
485 | ||
486 | static int journal_clean_one_cp_list(struct journal_head *jh, int *released) | |
487 | { | |
488 | struct journal_head *last_jh; | |
489 | struct journal_head *next_jh = jh; | |
490 | int ret, freed = 0; | |
491 | ||
492 | *released = 0; | |
493 | if (!jh) | |
494 | return 0; | |
495 | ||
496 | last_jh = jh->b_cpprev; | |
497 | do { | |
498 | jh = next_jh; | |
499 | next_jh = jh->b_cpnext; | |
932bb305 JK |
500 | ret = __try_to_free_cp_buf(jh); |
501 | if (ret) { | |
502 | freed++; | |
503 | if (ret == 2) { | |
504 | *released = 1; | |
505 | return freed; | |
470decc6 DK |
506 | } |
507 | } | |
508 | /* | |
509 | * This function only frees up some memory | |
510 | * if possible so we dont have an obligation | |
511 | * to finish processing. Bail out if preemption | |
512 | * requested: | |
513 | */ | |
514 | if (need_resched()) | |
515 | return freed; | |
516 | } while (jh != last_jh); | |
517 | ||
518 | return freed; | |
519 | } | |
520 | ||
521 | /* | |
522 | * journal_clean_checkpoint_list | |
523 | * | |
524 | * Find all the written-back checkpoint buffers in the journal and release them. | |
525 | * | |
526 | * Called with the journal locked. | |
527 | * Called with j_list_lock held. | |
528 | * Returns number of buffers reaped (for debug) | |
529 | */ | |
530 | ||
f7f4bccb | 531 | int __jbd2_journal_clean_checkpoint_list(journal_t *journal) |
470decc6 DK |
532 | { |
533 | transaction_t *transaction, *last_transaction, *next_transaction; | |
534 | int ret = 0; | |
535 | int released; | |
536 | ||
537 | transaction = journal->j_checkpoint_transactions; | |
538 | if (!transaction) | |
539 | goto out; | |
540 | ||
541 | last_transaction = transaction->t_cpprev; | |
542 | next_transaction = transaction; | |
543 | do { | |
544 | transaction = next_transaction; | |
545 | next_transaction = transaction->t_cpnext; | |
546 | ret += journal_clean_one_cp_list(transaction-> | |
547 | t_checkpoint_list, &released); | |
548 | /* | |
549 | * This function only frees up some memory if possible so we | |
550 | * dont have an obligation to finish processing. Bail out if | |
551 | * preemption requested: | |
552 | */ | |
553 | if (need_resched()) | |
554 | goto out; | |
555 | if (released) | |
556 | continue; | |
557 | /* | |
558 | * It is essential that we are as careful as in the case of | |
559 | * t_checkpoint_list with removing the buffer from the list as | |
560 | * we can possibly see not yet submitted buffers on io_list | |
561 | */ | |
562 | ret += journal_clean_one_cp_list(transaction-> | |
563 | t_checkpoint_io_list, &released); | |
564 | if (need_resched()) | |
565 | goto out; | |
566 | } while (transaction != last_transaction); | |
567 | out: | |
568 | return ret; | |
569 | } | |
570 | ||
571 | /* | |
572 | * journal_remove_checkpoint: called after a buffer has been committed | |
573 | * to disk (either by being write-back flushed to disk, or being | |
574 | * committed to the log). | |
575 | * | |
576 | * We cannot safely clean a transaction out of the log until all of the | |
577 | * buffer updates committed in that transaction have safely been stored | |
578 | * elsewhere on disk. To achieve this, all of the buffers in a | |
579 | * transaction need to be maintained on the transaction's checkpoint | |
580 | * lists until they have been rewritten, at which point this function is | |
581 | * called to remove the buffer from the existing transaction's | |
582 | * checkpoint lists. | |
583 | * | |
584 | * The function returns 1 if it frees the transaction, 0 otherwise. | |
de1b7941 | 585 | * The function can free jh and bh. |
470decc6 | 586 | * |
470decc6 | 587 | * This function is called with j_list_lock held. |
470decc6 | 588 | */ |
f7f4bccb | 589 | int __jbd2_journal_remove_checkpoint(struct journal_head *jh) |
470decc6 | 590 | { |
bf699327 | 591 | struct transaction_chp_stats_s *stats; |
470decc6 DK |
592 | transaction_t *transaction; |
593 | journal_t *journal; | |
594 | int ret = 0; | |
595 | ||
596 | JBUFFER_TRACE(jh, "entry"); | |
597 | ||
598 | if ((transaction = jh->b_cp_transaction) == NULL) { | |
599 | JBUFFER_TRACE(jh, "not on transaction"); | |
600 | goto out; | |
601 | } | |
602 | journal = transaction->t_journal; | |
603 | ||
de1b7941 | 604 | JBUFFER_TRACE(jh, "removing from transaction"); |
470decc6 DK |
605 | __buffer_unlink(jh); |
606 | jh->b_cp_transaction = NULL; | |
de1b7941 | 607 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
608 | |
609 | if (transaction->t_checkpoint_list != NULL || | |
610 | transaction->t_checkpoint_io_list != NULL) | |
611 | goto out; | |
470decc6 DK |
612 | |
613 | /* | |
614 | * There is one special case to worry about: if we have just pulled the | |
f5a7a6b0 JK |
615 | * buffer off a running or committing transaction's checkpoing list, |
616 | * then even if the checkpoint list is empty, the transaction obviously | |
617 | * cannot be dropped! | |
470decc6 | 618 | * |
f5a7a6b0 | 619 | * The locking here around t_state is a bit sleazy. |
f7f4bccb | 620 | * See the comment at the end of jbd2_journal_commit_transaction(). |
470decc6 | 621 | */ |
de1b7941 | 622 | if (transaction->t_state != T_FINISHED) |
470decc6 | 623 | goto out; |
470decc6 DK |
624 | |
625 | /* OK, that was the last buffer for the transaction: we can now | |
626 | safely remove this transaction from the log */ | |
bf699327 TT |
627 | stats = &transaction->t_chp_stats; |
628 | if (stats->cs_chp_time) | |
629 | stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time, | |
630 | jiffies); | |
631 | trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev, | |
632 | transaction->t_tid, stats); | |
470decc6 | 633 | |
f7f4bccb | 634 | __jbd2_journal_drop_transaction(journal, transaction); |
0c2022ec | 635 | jbd2_journal_free_transaction(transaction); |
470decc6 DK |
636 | ret = 1; |
637 | out: | |
470decc6 DK |
638 | return ret; |
639 | } | |
640 | ||
641 | /* | |
642 | * journal_insert_checkpoint: put a committed buffer onto a checkpoint | |
643 | * list so that we know when it is safe to clean the transaction out of | |
644 | * the log. | |
645 | * | |
646 | * Called with the journal locked. | |
647 | * Called with j_list_lock held. | |
648 | */ | |
f7f4bccb | 649 | void __jbd2_journal_insert_checkpoint(struct journal_head *jh, |
470decc6 DK |
650 | transaction_t *transaction) |
651 | { | |
652 | JBUFFER_TRACE(jh, "entry"); | |
653 | J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh))); | |
654 | J_ASSERT_JH(jh, jh->b_cp_transaction == NULL); | |
655 | ||
de1b7941 JK |
656 | /* Get reference for checkpointing transaction */ |
657 | jbd2_journal_grab_journal_head(jh2bh(jh)); | |
470decc6 DK |
658 | jh->b_cp_transaction = transaction; |
659 | ||
660 | if (!transaction->t_checkpoint_list) { | |
661 | jh->b_cpnext = jh->b_cpprev = jh; | |
662 | } else { | |
663 | jh->b_cpnext = transaction->t_checkpoint_list; | |
664 | jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev; | |
665 | jh->b_cpprev->b_cpnext = jh; | |
666 | jh->b_cpnext->b_cpprev = jh; | |
667 | } | |
668 | transaction->t_checkpoint_list = jh; | |
669 | } | |
670 | ||
671 | /* | |
672 | * We've finished with this transaction structure: adios... | |
673 | * | |
674 | * The transaction must have no links except for the checkpoint by this | |
675 | * point. | |
676 | * | |
677 | * Called with the journal locked. | |
678 | * Called with j_list_lock held. | |
679 | */ | |
680 | ||
f7f4bccb | 681 | void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
682 | { |
683 | assert_spin_locked(&journal->j_list_lock); | |
684 | if (transaction->t_cpnext) { | |
685 | transaction->t_cpnext->t_cpprev = transaction->t_cpprev; | |
686 | transaction->t_cpprev->t_cpnext = transaction->t_cpnext; | |
687 | if (journal->j_checkpoint_transactions == transaction) | |
688 | journal->j_checkpoint_transactions = | |
689 | transaction->t_cpnext; | |
690 | if (journal->j_checkpoint_transactions == transaction) | |
691 | journal->j_checkpoint_transactions = NULL; | |
692 | } | |
693 | ||
694 | J_ASSERT(transaction->t_state == T_FINISHED); | |
695 | J_ASSERT(transaction->t_buffers == NULL); | |
470decc6 | 696 | J_ASSERT(transaction->t_forget == NULL); |
470decc6 | 697 | J_ASSERT(transaction->t_shadow_list == NULL); |
470decc6 DK |
698 | J_ASSERT(transaction->t_checkpoint_list == NULL); |
699 | J_ASSERT(transaction->t_checkpoint_io_list == NULL); | |
a51dca9c | 700 | J_ASSERT(atomic_read(&transaction->t_updates) == 0); |
470decc6 DK |
701 | J_ASSERT(journal->j_committing_transaction != transaction); |
702 | J_ASSERT(journal->j_running_transaction != transaction); | |
703 | ||
2201c590 SA |
704 | trace_jbd2_drop_transaction(journal, transaction); |
705 | ||
470decc6 | 706 | jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid); |
470decc6 | 707 | } |