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1da177e4 LT |
1 | /* |
2 | * linux/fs/commit.c | |
3 | * | |
4 | * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 | |
5 | * | |
6 | * Copyright 1998 Red Hat corp --- 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 | * Journal commit routines for the generic filesystem journaling code; | |
13 | * part of the ext2fs journaling system. | |
14 | */ | |
15 | ||
16 | #include <linux/time.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/jbd.h> | |
19 | #include <linux/errno.h> | |
20 | #include <linux/slab.h> | |
21 | #include <linux/mm.h> | |
22 | #include <linux/pagemap.h> | |
23 | #include <linux/smp_lock.h> | |
24 | ||
25 | /* | |
26 | * Default IO end handler for temporary BJ_IO buffer_heads. | |
27 | */ | |
28 | static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate) | |
29 | { | |
30 | BUFFER_TRACE(bh, ""); | |
31 | if (uptodate) | |
32 | set_buffer_uptodate(bh); | |
33 | else | |
34 | clear_buffer_uptodate(bh); | |
35 | unlock_buffer(bh); | |
36 | } | |
37 | ||
38 | /* | |
39 | * When an ext3-ordered file is truncated, it is possible that many pages are | |
40 | * not sucessfully freed, because they are attached to a committing transaction. | |
41 | * After the transaction commits, these pages are left on the LRU, with no | |
42 | * ->mapping, and with attached buffers. These pages are trivially reclaimable | |
43 | * by the VM, but their apparent absence upsets the VM accounting, and it makes | |
44 | * the numbers in /proc/meminfo look odd. | |
45 | * | |
46 | * So here, we have a buffer which has just come off the forget list. Look to | |
47 | * see if we can strip all buffers from the backing page. | |
48 | * | |
49 | * Called under lock_journal(), and possibly under journal_datalist_lock. The | |
50 | * caller provided us with a ref against the buffer, and we drop that here. | |
51 | */ | |
52 | static void release_buffer_page(struct buffer_head *bh) | |
53 | { | |
54 | struct page *page; | |
55 | ||
56 | if (buffer_dirty(bh)) | |
57 | goto nope; | |
58 | if (atomic_read(&bh->b_count) != 1) | |
59 | goto nope; | |
60 | page = bh->b_page; | |
61 | if (!page) | |
62 | goto nope; | |
63 | if (page->mapping) | |
64 | goto nope; | |
65 | ||
66 | /* OK, it's a truncated page */ | |
67 | if (TestSetPageLocked(page)) | |
68 | goto nope; | |
69 | ||
70 | page_cache_get(page); | |
71 | __brelse(bh); | |
72 | try_to_free_buffers(page); | |
73 | unlock_page(page); | |
74 | page_cache_release(page); | |
75 | return; | |
76 | ||
77 | nope: | |
78 | __brelse(bh); | |
79 | } | |
80 | ||
81 | /* | |
82 | * Try to acquire jbd_lock_bh_state() against the buffer, when j_list_lock is | |
83 | * held. For ranking reasons we must trylock. If we lose, schedule away and | |
84 | * return 0. j_list_lock is dropped in this case. | |
85 | */ | |
86 | static int inverted_lock(journal_t *journal, struct buffer_head *bh) | |
87 | { | |
88 | if (!jbd_trylock_bh_state(bh)) { | |
89 | spin_unlock(&journal->j_list_lock); | |
90 | schedule(); | |
91 | return 0; | |
92 | } | |
93 | return 1; | |
94 | } | |
95 | ||
96 | /* Done it all: now write the commit record. We should have | |
97 | * cleaned up our previous buffers by now, so if we are in abort | |
98 | * mode we can now just skip the rest of the journal write | |
99 | * entirely. | |
100 | * | |
101 | * Returns 1 if the journal needs to be aborted or 0 on success | |
102 | */ | |
103 | static int journal_write_commit_record(journal_t *journal, | |
104 | transaction_t *commit_transaction) | |
105 | { | |
106 | struct journal_head *descriptor; | |
107 | struct buffer_head *bh; | |
108 | int i, ret; | |
109 | int barrier_done = 0; | |
110 | ||
111 | if (is_journal_aborted(journal)) | |
112 | return 0; | |
113 | ||
114 | descriptor = journal_get_descriptor_buffer(journal); | |
115 | if (!descriptor) | |
116 | return 1; | |
117 | ||
118 | bh = jh2bh(descriptor); | |
119 | ||
120 | /* AKPM: buglet - add `i' to tmp! */ | |
121 | for (i = 0; i < bh->b_size; i += 512) { | |
122 | journal_header_t *tmp = (journal_header_t*)bh->b_data; | |
123 | tmp->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); | |
124 | tmp->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK); | |
125 | tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid); | |
126 | } | |
127 | ||
128 | JBUFFER_TRACE(descriptor, "write commit block"); | |
129 | set_buffer_dirty(bh); | |
130 | if (journal->j_flags & JFS_BARRIER) { | |
131 | set_buffer_ordered(bh); | |
132 | barrier_done = 1; | |
133 | } | |
134 | ret = sync_dirty_buffer(bh); | |
135 | /* is it possible for another commit to fail at roughly | |
136 | * the same time as this one? If so, we don't want to | |
137 | * trust the barrier flag in the super, but instead want | |
138 | * to remember if we sent a barrier request | |
139 | */ | |
140 | if (ret == -EOPNOTSUPP && barrier_done) { | |
141 | char b[BDEVNAME_SIZE]; | |
142 | ||
143 | printk(KERN_WARNING | |
144 | "JBD: barrier-based sync failed on %s - " | |
145 | "disabling barriers\n", | |
146 | bdevname(journal->j_dev, b)); | |
147 | spin_lock(&journal->j_state_lock); | |
148 | journal->j_flags &= ~JFS_BARRIER; | |
149 | spin_unlock(&journal->j_state_lock); | |
150 | ||
151 | /* And try again, without the barrier */ | |
152 | clear_buffer_ordered(bh); | |
153 | set_buffer_uptodate(bh); | |
154 | set_buffer_dirty(bh); | |
155 | ret = sync_dirty_buffer(bh); | |
156 | } | |
157 | put_bh(bh); /* One for getblk() */ | |
158 | journal_put_journal_head(descriptor); | |
159 | ||
160 | return (ret == -EIO); | |
161 | } | |
162 | ||
163 | /* | |
164 | * journal_commit_transaction | |
165 | * | |
166 | * The primary function for committing a transaction to the log. This | |
167 | * function is called by the journal thread to begin a complete commit. | |
168 | */ | |
169 | void journal_commit_transaction(journal_t *journal) | |
170 | { | |
171 | transaction_t *commit_transaction; | |
172 | struct journal_head *jh, *new_jh, *descriptor; | |
173 | struct buffer_head **wbuf = journal->j_wbuf; | |
174 | int bufs; | |
175 | int flags; | |
176 | int err; | |
177 | unsigned long blocknr; | |
178 | char *tagp = NULL; | |
179 | journal_header_t *header; | |
180 | journal_block_tag_t *tag = NULL; | |
181 | int space_left = 0; | |
182 | int first_tag = 0; | |
183 | int tag_flag; | |
184 | int i; | |
185 | ||
186 | /* | |
187 | * First job: lock down the current transaction and wait for | |
188 | * all outstanding updates to complete. | |
189 | */ | |
190 | ||
191 | #ifdef COMMIT_STATS | |
192 | spin_lock(&journal->j_list_lock); | |
193 | summarise_journal_usage(journal); | |
194 | spin_unlock(&journal->j_list_lock); | |
195 | #endif | |
196 | ||
197 | /* Do we need to erase the effects of a prior journal_flush? */ | |
198 | if (journal->j_flags & JFS_FLUSHED) { | |
199 | jbd_debug(3, "super block updated\n"); | |
200 | journal_update_superblock(journal, 1); | |
201 | } else { | |
202 | jbd_debug(3, "superblock not updated\n"); | |
203 | } | |
204 | ||
205 | J_ASSERT(journal->j_running_transaction != NULL); | |
206 | J_ASSERT(journal->j_committing_transaction == NULL); | |
207 | ||
208 | commit_transaction = journal->j_running_transaction; | |
209 | J_ASSERT(commit_transaction->t_state == T_RUNNING); | |
210 | ||
211 | jbd_debug(1, "JBD: starting commit of transaction %d\n", | |
212 | commit_transaction->t_tid); | |
213 | ||
214 | spin_lock(&journal->j_state_lock); | |
215 | commit_transaction->t_state = T_LOCKED; | |
216 | ||
217 | spin_lock(&commit_transaction->t_handle_lock); | |
218 | while (commit_transaction->t_updates) { | |
219 | DEFINE_WAIT(wait); | |
220 | ||
221 | prepare_to_wait(&journal->j_wait_updates, &wait, | |
222 | TASK_UNINTERRUPTIBLE); | |
223 | if (commit_transaction->t_updates) { | |
224 | spin_unlock(&commit_transaction->t_handle_lock); | |
225 | spin_unlock(&journal->j_state_lock); | |
226 | schedule(); | |
227 | spin_lock(&journal->j_state_lock); | |
228 | spin_lock(&commit_transaction->t_handle_lock); | |
229 | } | |
230 | finish_wait(&journal->j_wait_updates, &wait); | |
231 | } | |
232 | spin_unlock(&commit_transaction->t_handle_lock); | |
233 | ||
234 | J_ASSERT (commit_transaction->t_outstanding_credits <= | |
235 | journal->j_max_transaction_buffers); | |
236 | ||
237 | /* | |
238 | * First thing we are allowed to do is to discard any remaining | |
239 | * BJ_Reserved buffers. Note, it is _not_ permissible to assume | |
240 | * that there are no such buffers: if a large filesystem | |
241 | * operation like a truncate needs to split itself over multiple | |
242 | * transactions, then it may try to do a journal_restart() while | |
243 | * there are still BJ_Reserved buffers outstanding. These must | |
244 | * be released cleanly from the current transaction. | |
245 | * | |
246 | * In this case, the filesystem must still reserve write access | |
247 | * again before modifying the buffer in the new transaction, but | |
248 | * we do not require it to remember exactly which old buffers it | |
249 | * has reserved. This is consistent with the existing behaviour | |
250 | * that multiple journal_get_write_access() calls to the same | |
251 | * buffer are perfectly permissable. | |
252 | */ | |
253 | while (commit_transaction->t_reserved_list) { | |
254 | jh = commit_transaction->t_reserved_list; | |
255 | JBUFFER_TRACE(jh, "reserved, unused: refile"); | |
256 | /* | |
257 | * A journal_get_undo_access()+journal_release_buffer() may | |
258 | * leave undo-committed data. | |
259 | */ | |
260 | if (jh->b_committed_data) { | |
261 | struct buffer_head *bh = jh2bh(jh); | |
262 | ||
263 | jbd_lock_bh_state(bh); | |
ea817398 | 264 | jbd_slab_free(jh->b_committed_data, bh->b_size); |
f99d49ad | 265 | jh->b_committed_data = NULL; |
1da177e4 LT |
266 | jbd_unlock_bh_state(bh); |
267 | } | |
268 | journal_refile_buffer(journal, jh); | |
269 | } | |
270 | ||
271 | /* | |
272 | * Now try to drop any written-back buffers from the journal's | |
273 | * checkpoint lists. We do this *before* commit because it potentially | |
274 | * frees some memory | |
275 | */ | |
276 | spin_lock(&journal->j_list_lock); | |
277 | __journal_clean_checkpoint_list(journal); | |
278 | spin_unlock(&journal->j_list_lock); | |
279 | ||
280 | jbd_debug (3, "JBD: commit phase 1\n"); | |
281 | ||
282 | /* | |
283 | * Switch to a new revoke table. | |
284 | */ | |
285 | journal_switch_revoke_table(journal); | |
286 | ||
287 | commit_transaction->t_state = T_FLUSH; | |
288 | journal->j_committing_transaction = commit_transaction; | |
289 | journal->j_running_transaction = NULL; | |
290 | commit_transaction->t_log_start = journal->j_head; | |
291 | wake_up(&journal->j_wait_transaction_locked); | |
292 | spin_unlock(&journal->j_state_lock); | |
293 | ||
294 | jbd_debug (3, "JBD: commit phase 2\n"); | |
295 | ||
296 | /* | |
297 | * First, drop modified flag: all accesses to the buffers | |
298 | * will be tracked for a new trasaction only -bzzz | |
299 | */ | |
300 | spin_lock(&journal->j_list_lock); | |
301 | if (commit_transaction->t_buffers) { | |
302 | new_jh = jh = commit_transaction->t_buffers->b_tnext; | |
303 | do { | |
304 | J_ASSERT_JH(new_jh, new_jh->b_modified == 1 || | |
305 | new_jh->b_modified == 0); | |
306 | new_jh->b_modified = 0; | |
307 | new_jh = new_jh->b_tnext; | |
308 | } while (new_jh != jh); | |
309 | } | |
310 | spin_unlock(&journal->j_list_lock); | |
311 | ||
312 | /* | |
313 | * Now start flushing things to disk, in the order they appear | |
314 | * on the transaction lists. Data blocks go first. | |
315 | */ | |
316 | ||
317 | err = 0; | |
318 | /* | |
319 | * Whenever we unlock the journal and sleep, things can get added | |
320 | * onto ->t_sync_datalist, so we have to keep looping back to | |
321 | * write_out_data until we *know* that the list is empty. | |
322 | */ | |
323 | bufs = 0; | |
324 | /* | |
325 | * Cleanup any flushed data buffers from the data list. Even in | |
326 | * abort mode, we want to flush this out as soon as possible. | |
327 | */ | |
328 | write_out_data: | |
329 | cond_resched(); | |
330 | spin_lock(&journal->j_list_lock); | |
331 | ||
332 | while (commit_transaction->t_sync_datalist) { | |
333 | struct buffer_head *bh; | |
334 | ||
335 | jh = commit_transaction->t_sync_datalist; | |
336 | commit_transaction->t_sync_datalist = jh->b_tnext; | |
337 | bh = jh2bh(jh); | |
338 | if (buffer_locked(bh)) { | |
339 | BUFFER_TRACE(bh, "locked"); | |
340 | if (!inverted_lock(journal, bh)) | |
341 | goto write_out_data; | |
342 | __journal_temp_unlink_buffer(jh); | |
343 | __journal_file_buffer(jh, commit_transaction, | |
344 | BJ_Locked); | |
345 | jbd_unlock_bh_state(bh); | |
346 | if (lock_need_resched(&journal->j_list_lock)) { | |
347 | spin_unlock(&journal->j_list_lock); | |
348 | goto write_out_data; | |
349 | } | |
350 | } else { | |
351 | if (buffer_dirty(bh)) { | |
352 | BUFFER_TRACE(bh, "start journal writeout"); | |
353 | get_bh(bh); | |
354 | wbuf[bufs++] = bh; | |
355 | if (bufs == journal->j_wbufsize) { | |
356 | jbd_debug(2, "submit %d writes\n", | |
357 | bufs); | |
358 | spin_unlock(&journal->j_list_lock); | |
26707699 | 359 | ll_rw_block(SWRITE, bufs, wbuf); |
1da177e4 LT |
360 | journal_brelse_array(wbuf, bufs); |
361 | bufs = 0; | |
362 | goto write_out_data; | |
363 | } | |
364 | } else { | |
365 | BUFFER_TRACE(bh, "writeout complete: unfile"); | |
366 | if (!inverted_lock(journal, bh)) | |
367 | goto write_out_data; | |
368 | __journal_unfile_buffer(jh); | |
369 | jbd_unlock_bh_state(bh); | |
370 | journal_remove_journal_head(bh); | |
371 | put_bh(bh); | |
372 | if (lock_need_resched(&journal->j_list_lock)) { | |
373 | spin_unlock(&journal->j_list_lock); | |
374 | goto write_out_data; | |
375 | } | |
376 | } | |
377 | } | |
378 | } | |
379 | ||
380 | if (bufs) { | |
381 | spin_unlock(&journal->j_list_lock); | |
26707699 | 382 | ll_rw_block(SWRITE, bufs, wbuf); |
1da177e4 LT |
383 | journal_brelse_array(wbuf, bufs); |
384 | spin_lock(&journal->j_list_lock); | |
385 | } | |
386 | ||
387 | /* | |
388 | * Wait for all previously submitted IO to complete. | |
389 | */ | |
390 | while (commit_transaction->t_locked_list) { | |
391 | struct buffer_head *bh; | |
392 | ||
393 | jh = commit_transaction->t_locked_list->b_tprev; | |
394 | bh = jh2bh(jh); | |
395 | get_bh(bh); | |
396 | if (buffer_locked(bh)) { | |
397 | spin_unlock(&journal->j_list_lock); | |
398 | wait_on_buffer(bh); | |
399 | if (unlikely(!buffer_uptodate(bh))) | |
400 | err = -EIO; | |
401 | spin_lock(&journal->j_list_lock); | |
402 | } | |
403 | if (!inverted_lock(journal, bh)) { | |
404 | put_bh(bh); | |
405 | spin_lock(&journal->j_list_lock); | |
406 | continue; | |
407 | } | |
408 | if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) { | |
409 | __journal_unfile_buffer(jh); | |
410 | jbd_unlock_bh_state(bh); | |
411 | journal_remove_journal_head(bh); | |
412 | put_bh(bh); | |
413 | } else { | |
414 | jbd_unlock_bh_state(bh); | |
415 | } | |
416 | put_bh(bh); | |
417 | cond_resched_lock(&journal->j_list_lock); | |
418 | } | |
419 | spin_unlock(&journal->j_list_lock); | |
420 | ||
421 | if (err) | |
422 | __journal_abort_hard(journal); | |
423 | ||
424 | journal_write_revoke_records(journal, commit_transaction); | |
425 | ||
426 | jbd_debug(3, "JBD: commit phase 2\n"); | |
427 | ||
428 | /* | |
429 | * If we found any dirty or locked buffers, then we should have | |
430 | * looped back up to the write_out_data label. If there weren't | |
431 | * any then journal_clean_data_list should have wiped the list | |
432 | * clean by now, so check that it is in fact empty. | |
433 | */ | |
434 | J_ASSERT (commit_transaction->t_sync_datalist == NULL); | |
435 | ||
436 | jbd_debug (3, "JBD: commit phase 3\n"); | |
437 | ||
438 | /* | |
439 | * Way to go: we have now written out all of the data for a | |
440 | * transaction! Now comes the tricky part: we need to write out | |
441 | * metadata. Loop over the transaction's entire buffer list: | |
442 | */ | |
443 | commit_transaction->t_state = T_COMMIT; | |
444 | ||
445 | descriptor = NULL; | |
446 | bufs = 0; | |
447 | while (commit_transaction->t_buffers) { | |
448 | ||
449 | /* Find the next buffer to be journaled... */ | |
450 | ||
451 | jh = commit_transaction->t_buffers; | |
452 | ||
453 | /* If we're in abort mode, we just un-journal the buffer and | |
454 | release it for background writing. */ | |
455 | ||
456 | if (is_journal_aborted(journal)) { | |
457 | JBUFFER_TRACE(jh, "journal is aborting: refile"); | |
458 | journal_refile_buffer(journal, jh); | |
459 | /* If that was the last one, we need to clean up | |
460 | * any descriptor buffers which may have been | |
461 | * already allocated, even if we are now | |
462 | * aborting. */ | |
463 | if (!commit_transaction->t_buffers) | |
464 | goto start_journal_io; | |
465 | continue; | |
466 | } | |
467 | ||
468 | /* Make sure we have a descriptor block in which to | |
469 | record the metadata buffer. */ | |
470 | ||
471 | if (!descriptor) { | |
472 | struct buffer_head *bh; | |
473 | ||
474 | J_ASSERT (bufs == 0); | |
475 | ||
476 | jbd_debug(4, "JBD: get descriptor\n"); | |
477 | ||
478 | descriptor = journal_get_descriptor_buffer(journal); | |
479 | if (!descriptor) { | |
480 | __journal_abort_hard(journal); | |
481 | continue; | |
482 | } | |
483 | ||
484 | bh = jh2bh(descriptor); | |
485 | jbd_debug(4, "JBD: got buffer %llu (%p)\n", | |
486 | (unsigned long long)bh->b_blocknr, bh->b_data); | |
487 | header = (journal_header_t *)&bh->b_data[0]; | |
488 | header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); | |
489 | header->h_blocktype = cpu_to_be32(JFS_DESCRIPTOR_BLOCK); | |
490 | header->h_sequence = cpu_to_be32(commit_transaction->t_tid); | |
491 | ||
492 | tagp = &bh->b_data[sizeof(journal_header_t)]; | |
493 | space_left = bh->b_size - sizeof(journal_header_t); | |
494 | first_tag = 1; | |
495 | set_buffer_jwrite(bh); | |
496 | set_buffer_dirty(bh); | |
497 | wbuf[bufs++] = bh; | |
498 | ||
499 | /* Record it so that we can wait for IO | |
500 | completion later */ | |
501 | BUFFER_TRACE(bh, "ph3: file as descriptor"); | |
502 | journal_file_buffer(descriptor, commit_transaction, | |
503 | BJ_LogCtl); | |
504 | } | |
505 | ||
506 | /* Where is the buffer to be written? */ | |
507 | ||
508 | err = journal_next_log_block(journal, &blocknr); | |
509 | /* If the block mapping failed, just abandon the buffer | |
510 | and repeat this loop: we'll fall into the | |
511 | refile-on-abort condition above. */ | |
512 | if (err) { | |
513 | __journal_abort_hard(journal); | |
514 | continue; | |
515 | } | |
516 | ||
517 | /* | |
518 | * start_this_handle() uses t_outstanding_credits to determine | |
519 | * the free space in the log, but this counter is changed | |
520 | * by journal_next_log_block() also. | |
521 | */ | |
522 | commit_transaction->t_outstanding_credits--; | |
523 | ||
524 | /* Bump b_count to prevent truncate from stumbling over | |
525 | the shadowed buffer! @@@ This can go if we ever get | |
526 | rid of the BJ_IO/BJ_Shadow pairing of buffers. */ | |
527 | atomic_inc(&jh2bh(jh)->b_count); | |
528 | ||
529 | /* Make a temporary IO buffer with which to write it out | |
530 | (this will requeue both the metadata buffer and the | |
531 | temporary IO buffer). new_bh goes on BJ_IO*/ | |
532 | ||
533 | set_bit(BH_JWrite, &jh2bh(jh)->b_state); | |
534 | /* | |
535 | * akpm: journal_write_metadata_buffer() sets | |
536 | * new_bh->b_transaction to commit_transaction. | |
537 | * We need to clean this up before we release new_bh | |
538 | * (which is of type BJ_IO) | |
539 | */ | |
540 | JBUFFER_TRACE(jh, "ph3: write metadata"); | |
541 | flags = journal_write_metadata_buffer(commit_transaction, | |
542 | jh, &new_jh, blocknr); | |
543 | set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); | |
544 | wbuf[bufs++] = jh2bh(new_jh); | |
545 | ||
546 | /* Record the new block's tag in the current descriptor | |
547 | buffer */ | |
548 | ||
549 | tag_flag = 0; | |
550 | if (flags & 1) | |
551 | tag_flag |= JFS_FLAG_ESCAPE; | |
552 | if (!first_tag) | |
553 | tag_flag |= JFS_FLAG_SAME_UUID; | |
554 | ||
555 | tag = (journal_block_tag_t *) tagp; | |
556 | tag->t_blocknr = cpu_to_be32(jh2bh(jh)->b_blocknr); | |
557 | tag->t_flags = cpu_to_be32(tag_flag); | |
558 | tagp += sizeof(journal_block_tag_t); | |
559 | space_left -= sizeof(journal_block_tag_t); | |
560 | ||
561 | if (first_tag) { | |
562 | memcpy (tagp, journal->j_uuid, 16); | |
563 | tagp += 16; | |
564 | space_left -= 16; | |
565 | first_tag = 0; | |
566 | } | |
567 | ||
568 | /* If there's no more to do, or if the descriptor is full, | |
569 | let the IO rip! */ | |
570 | ||
571 | if (bufs == journal->j_wbufsize || | |
572 | commit_transaction->t_buffers == NULL || | |
573 | space_left < sizeof(journal_block_tag_t) + 16) { | |
574 | ||
575 | jbd_debug(4, "JBD: Submit %d IOs\n", bufs); | |
576 | ||
577 | /* Write an end-of-descriptor marker before | |
578 | submitting the IOs. "tag" still points to | |
579 | the last tag we set up. */ | |
580 | ||
581 | tag->t_flags |= cpu_to_be32(JFS_FLAG_LAST_TAG); | |
582 | ||
583 | start_journal_io: | |
584 | for (i = 0; i < bufs; i++) { | |
585 | struct buffer_head *bh = wbuf[i]; | |
586 | lock_buffer(bh); | |
587 | clear_buffer_dirty(bh); | |
588 | set_buffer_uptodate(bh); | |
589 | bh->b_end_io = journal_end_buffer_io_sync; | |
590 | submit_bh(WRITE, bh); | |
591 | } | |
592 | cond_resched(); | |
593 | ||
594 | /* Force a new descriptor to be generated next | |
595 | time round the loop. */ | |
596 | descriptor = NULL; | |
597 | bufs = 0; | |
598 | } | |
599 | } | |
600 | ||
601 | /* Lo and behold: we have just managed to send a transaction to | |
602 | the log. Before we can commit it, wait for the IO so far to | |
603 | complete. Control buffers being written are on the | |
604 | transaction's t_log_list queue, and metadata buffers are on | |
605 | the t_iobuf_list queue. | |
606 | ||
607 | Wait for the buffers in reverse order. That way we are | |
608 | less likely to be woken up until all IOs have completed, and | |
609 | so we incur less scheduling load. | |
610 | */ | |
611 | ||
612 | jbd_debug(3, "JBD: commit phase 4\n"); | |
613 | ||
614 | /* | |
615 | * akpm: these are BJ_IO, and j_list_lock is not needed. | |
616 | * See __journal_try_to_free_buffer. | |
617 | */ | |
618 | wait_for_iobuf: | |
619 | while (commit_transaction->t_iobuf_list != NULL) { | |
620 | struct buffer_head *bh; | |
621 | ||
622 | jh = commit_transaction->t_iobuf_list->b_tprev; | |
623 | bh = jh2bh(jh); | |
624 | if (buffer_locked(bh)) { | |
625 | wait_on_buffer(bh); | |
626 | goto wait_for_iobuf; | |
627 | } | |
628 | if (cond_resched()) | |
629 | goto wait_for_iobuf; | |
630 | ||
631 | if (unlikely(!buffer_uptodate(bh))) | |
632 | err = -EIO; | |
633 | ||
634 | clear_buffer_jwrite(bh); | |
635 | ||
636 | JBUFFER_TRACE(jh, "ph4: unfile after journal write"); | |
637 | journal_unfile_buffer(journal, jh); | |
638 | ||
639 | /* | |
640 | * ->t_iobuf_list should contain only dummy buffer_heads | |
641 | * which were created by journal_write_metadata_buffer(). | |
642 | */ | |
643 | BUFFER_TRACE(bh, "dumping temporary bh"); | |
644 | journal_put_journal_head(jh); | |
645 | __brelse(bh); | |
646 | J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); | |
647 | free_buffer_head(bh); | |
648 | ||
649 | /* We also have to unlock and free the corresponding | |
650 | shadowed buffer */ | |
651 | jh = commit_transaction->t_shadow_list->b_tprev; | |
652 | bh = jh2bh(jh); | |
653 | clear_bit(BH_JWrite, &bh->b_state); | |
654 | J_ASSERT_BH(bh, buffer_jbddirty(bh)); | |
655 | ||
656 | /* The metadata is now released for reuse, but we need | |
657 | to remember it against this transaction so that when | |
658 | we finally commit, we can do any checkpointing | |
659 | required. */ | |
660 | JBUFFER_TRACE(jh, "file as BJ_Forget"); | |
661 | journal_file_buffer(jh, commit_transaction, BJ_Forget); | |
662 | /* Wake up any transactions which were waiting for this | |
663 | IO to complete */ | |
664 | wake_up_bit(&bh->b_state, BH_Unshadow); | |
665 | JBUFFER_TRACE(jh, "brelse shadowed buffer"); | |
666 | __brelse(bh); | |
667 | } | |
668 | ||
669 | J_ASSERT (commit_transaction->t_shadow_list == NULL); | |
670 | ||
671 | jbd_debug(3, "JBD: commit phase 5\n"); | |
672 | ||
673 | /* Here we wait for the revoke record and descriptor record buffers */ | |
674 | wait_for_ctlbuf: | |
675 | while (commit_transaction->t_log_list != NULL) { | |
676 | struct buffer_head *bh; | |
677 | ||
678 | jh = commit_transaction->t_log_list->b_tprev; | |
679 | bh = jh2bh(jh); | |
680 | if (buffer_locked(bh)) { | |
681 | wait_on_buffer(bh); | |
682 | goto wait_for_ctlbuf; | |
683 | } | |
684 | if (cond_resched()) | |
685 | goto wait_for_ctlbuf; | |
686 | ||
687 | if (unlikely(!buffer_uptodate(bh))) | |
688 | err = -EIO; | |
689 | ||
690 | BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); | |
691 | clear_buffer_jwrite(bh); | |
692 | journal_unfile_buffer(journal, jh); | |
693 | journal_put_journal_head(jh); | |
694 | __brelse(bh); /* One for getblk */ | |
695 | /* AKPM: bforget here */ | |
696 | } | |
697 | ||
698 | jbd_debug(3, "JBD: commit phase 6\n"); | |
699 | ||
700 | if (journal_write_commit_record(journal, commit_transaction)) | |
701 | err = -EIO; | |
702 | ||
703 | if (err) | |
704 | __journal_abort_hard(journal); | |
705 | ||
706 | /* End of a transaction! Finally, we can do checkpoint | |
707 | processing: any buffers committed as a result of this | |
708 | transaction can be removed from any checkpoint list it was on | |
709 | before. */ | |
710 | ||
711 | jbd_debug(3, "JBD: commit phase 7\n"); | |
712 | ||
713 | J_ASSERT(commit_transaction->t_sync_datalist == NULL); | |
714 | J_ASSERT(commit_transaction->t_buffers == NULL); | |
715 | J_ASSERT(commit_transaction->t_checkpoint_list == NULL); | |
716 | J_ASSERT(commit_transaction->t_iobuf_list == NULL); | |
717 | J_ASSERT(commit_transaction->t_shadow_list == NULL); | |
718 | J_ASSERT(commit_transaction->t_log_list == NULL); | |
719 | ||
720 | restart_loop: | |
e6c9f5c1 JK |
721 | /* |
722 | * As there are other places (journal_unmap_buffer()) adding buffers | |
723 | * to this list we have to be careful and hold the j_list_lock. | |
724 | */ | |
725 | spin_lock(&journal->j_list_lock); | |
1da177e4 LT |
726 | while (commit_transaction->t_forget) { |
727 | transaction_t *cp_transaction; | |
728 | struct buffer_head *bh; | |
729 | ||
730 | jh = commit_transaction->t_forget; | |
e6c9f5c1 | 731 | spin_unlock(&journal->j_list_lock); |
1da177e4 LT |
732 | bh = jh2bh(jh); |
733 | jbd_lock_bh_state(bh); | |
734 | J_ASSERT_JH(jh, jh->b_transaction == commit_transaction || | |
735 | jh->b_transaction == journal->j_running_transaction); | |
736 | ||
737 | /* | |
738 | * If there is undo-protected committed data against | |
739 | * this buffer, then we can remove it now. If it is a | |
740 | * buffer needing such protection, the old frozen_data | |
741 | * field now points to a committed version of the | |
742 | * buffer, so rotate that field to the new committed | |
743 | * data. | |
744 | * | |
745 | * Otherwise, we can just throw away the frozen data now. | |
746 | */ | |
747 | if (jh->b_committed_data) { | |
ea817398 | 748 | jbd_slab_free(jh->b_committed_data, bh->b_size); |
1da177e4 LT |
749 | jh->b_committed_data = NULL; |
750 | if (jh->b_frozen_data) { | |
751 | jh->b_committed_data = jh->b_frozen_data; | |
752 | jh->b_frozen_data = NULL; | |
753 | } | |
754 | } else if (jh->b_frozen_data) { | |
ea817398 | 755 | jbd_slab_free(jh->b_frozen_data, bh->b_size); |
1da177e4 LT |
756 | jh->b_frozen_data = NULL; |
757 | } | |
758 | ||
759 | spin_lock(&journal->j_list_lock); | |
760 | cp_transaction = jh->b_cp_transaction; | |
761 | if (cp_transaction) { | |
762 | JBUFFER_TRACE(jh, "remove from old cp transaction"); | |
763 | __journal_remove_checkpoint(jh); | |
764 | } | |
765 | ||
766 | /* Only re-checkpoint the buffer_head if it is marked | |
767 | * dirty. If the buffer was added to the BJ_Forget list | |
768 | * by journal_forget, it may no longer be dirty and | |
769 | * there's no point in keeping a checkpoint record for | |
770 | * it. */ | |
771 | ||
772 | /* A buffer which has been freed while still being | |
773 | * journaled by a previous transaction may end up still | |
774 | * being dirty here, but we want to avoid writing back | |
775 | * that buffer in the future now that the last use has | |
776 | * been committed. That's not only a performance gain, | |
777 | * it also stops aliasing problems if the buffer is left | |
778 | * behind for writeback and gets reallocated for another | |
779 | * use in a different page. */ | |
780 | if (buffer_freed(bh)) { | |
781 | clear_buffer_freed(bh); | |
782 | clear_buffer_jbddirty(bh); | |
783 | } | |
784 | ||
785 | if (buffer_jbddirty(bh)) { | |
786 | JBUFFER_TRACE(jh, "add to new checkpointing trans"); | |
787 | __journal_insert_checkpoint(jh, commit_transaction); | |
788 | JBUFFER_TRACE(jh, "refile for checkpoint writeback"); | |
789 | __journal_refile_buffer(jh); | |
790 | jbd_unlock_bh_state(bh); | |
791 | } else { | |
792 | J_ASSERT_BH(bh, !buffer_dirty(bh)); | |
9ada7340 JK |
793 | /* The buffer on BJ_Forget list and not jbddirty means |
794 | * it has been freed by this transaction and hence it | |
795 | * could not have been reallocated until this | |
796 | * transaction has committed. *BUT* it could be | |
797 | * reallocated once we have written all the data to | |
798 | * disk and before we process the buffer on BJ_Forget | |
799 | * list. */ | |
800 | JBUFFER_TRACE(jh, "refile or unfile freed buffer"); | |
801 | __journal_refile_buffer(jh); | |
802 | if (!jh->b_transaction) { | |
803 | jbd_unlock_bh_state(bh); | |
804 | /* needs a brelse */ | |
805 | journal_remove_journal_head(bh); | |
806 | release_buffer_page(bh); | |
807 | } else | |
808 | jbd_unlock_bh_state(bh); | |
1da177e4 | 809 | } |
e6c9f5c1 JK |
810 | cond_resched_lock(&journal->j_list_lock); |
811 | } | |
812 | spin_unlock(&journal->j_list_lock); | |
813 | /* | |
814 | * This is a bit sleazy. We borrow j_list_lock to protect | |
815 | * journal->j_committing_transaction in __journal_remove_checkpoint. | |
816 | * Really, __journal_remove_checkpoint should be using j_state_lock but | |
817 | * it's a bit hassle to hold that across __journal_remove_checkpoint | |
818 | */ | |
819 | spin_lock(&journal->j_state_lock); | |
820 | spin_lock(&journal->j_list_lock); | |
821 | /* | |
822 | * Now recheck if some buffers did not get attached to the transaction | |
823 | * while the lock was dropped... | |
824 | */ | |
825 | if (commit_transaction->t_forget) { | |
1da177e4 | 826 | spin_unlock(&journal->j_list_lock); |
e6c9f5c1 JK |
827 | spin_unlock(&journal->j_state_lock); |
828 | goto restart_loop; | |
1da177e4 LT |
829 | } |
830 | ||
831 | /* Done with this transaction! */ | |
832 | ||
833 | jbd_debug(3, "JBD: commit phase 8\n"); | |
834 | ||
835 | J_ASSERT(commit_transaction->t_state == T_COMMIT); | |
836 | ||
1da177e4 LT |
837 | commit_transaction->t_state = T_FINISHED; |
838 | J_ASSERT(commit_transaction == journal->j_committing_transaction); | |
839 | journal->j_commit_sequence = commit_transaction->t_tid; | |
840 | journal->j_committing_transaction = NULL; | |
841 | spin_unlock(&journal->j_state_lock); | |
842 | ||
7c8903f6 | 843 | if (commit_transaction->t_checkpoint_list == NULL) { |
1da177e4 LT |
844 | __journal_drop_transaction(journal, commit_transaction); |
845 | } else { | |
846 | if (journal->j_checkpoint_transactions == NULL) { | |
847 | journal->j_checkpoint_transactions = commit_transaction; | |
848 | commit_transaction->t_cpnext = commit_transaction; | |
849 | commit_transaction->t_cpprev = commit_transaction; | |
850 | } else { | |
851 | commit_transaction->t_cpnext = | |
852 | journal->j_checkpoint_transactions; | |
853 | commit_transaction->t_cpprev = | |
854 | commit_transaction->t_cpnext->t_cpprev; | |
855 | commit_transaction->t_cpnext->t_cpprev = | |
856 | commit_transaction; | |
857 | commit_transaction->t_cpprev->t_cpnext = | |
858 | commit_transaction; | |
859 | } | |
860 | } | |
861 | spin_unlock(&journal->j_list_lock); | |
862 | ||
863 | jbd_debug(1, "JBD: commit %d complete, head %d\n", | |
864 | journal->j_commit_sequence, journal->j_tail_sequence); | |
865 | ||
866 | wake_up(&journal->j_wait_done_commit); | |
867 | } |