Commit | Line | Data |
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1da177e4 | 1 | /* |
f30c2269 | 2 | * linux/fs/jbd/commit.c |
1da177e4 LT |
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> | |
1da177e4 LT |
23 | |
24 | /* | |
25 | * Default IO end handler for temporary BJ_IO buffer_heads. | |
26 | */ | |
27 | static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate) | |
28 | { | |
29 | BUFFER_TRACE(bh, ""); | |
30 | if (uptodate) | |
31 | set_buffer_uptodate(bh); | |
32 | else | |
33 | clear_buffer_uptodate(bh); | |
34 | unlock_buffer(bh); | |
35 | } | |
36 | ||
37 | /* | |
38 | * When an ext3-ordered file is truncated, it is possible that many pages are | |
39 | * not sucessfully freed, because they are attached to a committing transaction. | |
40 | * After the transaction commits, these pages are left on the LRU, with no | |
41 | * ->mapping, and with attached buffers. These pages are trivially reclaimable | |
42 | * by the VM, but their apparent absence upsets the VM accounting, and it makes | |
43 | * the numbers in /proc/meminfo look odd. | |
44 | * | |
45 | * So here, we have a buffer which has just come off the forget list. Look to | |
46 | * see if we can strip all buffers from the backing page. | |
47 | * | |
48 | * Called under lock_journal(), and possibly under journal_datalist_lock. The | |
49 | * caller provided us with a ref against the buffer, and we drop that here. | |
50 | */ | |
51 | static void release_buffer_page(struct buffer_head *bh) | |
52 | { | |
53 | struct page *page; | |
54 | ||
55 | if (buffer_dirty(bh)) | |
56 | goto nope; | |
57 | if (atomic_read(&bh->b_count) != 1) | |
58 | goto nope; | |
59 | page = bh->b_page; | |
60 | if (!page) | |
61 | goto nope; | |
62 | if (page->mapping) | |
63 | goto nope; | |
64 | ||
65 | /* OK, it's a truncated page */ | |
66 | if (TestSetPageLocked(page)) | |
67 | goto nope; | |
68 | ||
69 | page_cache_get(page); | |
70 | __brelse(bh); | |
71 | try_to_free_buffers(page); | |
72 | unlock_page(page); | |
73 | page_cache_release(page); | |
74 | return; | |
75 | ||
76 | nope: | |
77 | __brelse(bh); | |
78 | } | |
79 | ||
80 | /* | |
81 | * Try to acquire jbd_lock_bh_state() against the buffer, when j_list_lock is | |
82 | * held. For ranking reasons we must trylock. If we lose, schedule away and | |
83 | * return 0. j_list_lock is dropped in this case. | |
84 | */ | |
85 | static int inverted_lock(journal_t *journal, struct buffer_head *bh) | |
86 | { | |
87 | if (!jbd_trylock_bh_state(bh)) { | |
88 | spin_unlock(&journal->j_list_lock); | |
89 | schedule(); | |
90 | return 0; | |
91 | } | |
92 | return 1; | |
93 | } | |
94 | ||
95 | /* Done it all: now write the commit record. We should have | |
96 | * cleaned up our previous buffers by now, so if we are in abort | |
97 | * mode we can now just skip the rest of the journal write | |
98 | * entirely. | |
99 | * | |
100 | * Returns 1 if the journal needs to be aborted or 0 on success | |
101 | */ | |
102 | static int journal_write_commit_record(journal_t *journal, | |
103 | transaction_t *commit_transaction) | |
104 | { | |
105 | struct journal_head *descriptor; | |
106 | struct buffer_head *bh; | |
107 | int i, ret; | |
108 | int barrier_done = 0; | |
109 | ||
110 | if (is_journal_aborted(journal)) | |
111 | return 0; | |
112 | ||
113 | descriptor = journal_get_descriptor_buffer(journal); | |
114 | if (!descriptor) | |
115 | return 1; | |
116 | ||
117 | bh = jh2bh(descriptor); | |
118 | ||
119 | /* AKPM: buglet - add `i' to tmp! */ | |
120 | for (i = 0; i < bh->b_size; i += 512) { | |
121 | journal_header_t *tmp = (journal_header_t*)bh->b_data; | |
122 | tmp->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); | |
123 | tmp->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK); | |
124 | tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid); | |
125 | } | |
126 | ||
127 | JBUFFER_TRACE(descriptor, "write commit block"); | |
128 | set_buffer_dirty(bh); | |
129 | if (journal->j_flags & JFS_BARRIER) { | |
130 | set_buffer_ordered(bh); | |
131 | barrier_done = 1; | |
132 | } | |
133 | ret = sync_dirty_buffer(bh); | |
134 | /* is it possible for another commit to fail at roughly | |
135 | * the same time as this one? If so, we don't want to | |
136 | * trust the barrier flag in the super, but instead want | |
137 | * to remember if we sent a barrier request | |
138 | */ | |
139 | if (ret == -EOPNOTSUPP && barrier_done) { | |
140 | char b[BDEVNAME_SIZE]; | |
141 | ||
142 | printk(KERN_WARNING | |
143 | "JBD: barrier-based sync failed on %s - " | |
144 | "disabling barriers\n", | |
145 | bdevname(journal->j_dev, b)); | |
146 | spin_lock(&journal->j_state_lock); | |
147 | journal->j_flags &= ~JFS_BARRIER; | |
148 | spin_unlock(&journal->j_state_lock); | |
149 | ||
150 | /* And try again, without the barrier */ | |
151 | clear_buffer_ordered(bh); | |
152 | set_buffer_uptodate(bh); | |
153 | set_buffer_dirty(bh); | |
154 | ret = sync_dirty_buffer(bh); | |
155 | } | |
156 | put_bh(bh); /* One for getblk() */ | |
157 | journal_put_journal_head(descriptor); | |
158 | ||
159 | return (ret == -EIO); | |
160 | } | |
161 | ||
3998b930 JK |
162 | static void journal_do_submit_data(struct buffer_head **wbuf, int bufs) |
163 | { | |
164 | int i; | |
165 | ||
166 | for (i = 0; i < bufs; i++) { | |
167 | wbuf[i]->b_end_io = end_buffer_write_sync; | |
168 | /* We use-up our safety reference in submit_bh() */ | |
169 | submit_bh(WRITE, wbuf[i]); | |
170 | } | |
171 | } | |
172 | ||
173 | /* | |
174 | * Submit all the data buffers to disk | |
175 | */ | |
176 | static void journal_submit_data_buffers(journal_t *journal, | |
177 | transaction_t *commit_transaction) | |
178 | { | |
179 | struct journal_head *jh; | |
180 | struct buffer_head *bh; | |
181 | int locked; | |
182 | int bufs = 0; | |
183 | struct buffer_head **wbuf = journal->j_wbuf; | |
184 | ||
185 | /* | |
186 | * Whenever we unlock the journal and sleep, things can get added | |
187 | * onto ->t_sync_datalist, so we have to keep looping back to | |
188 | * write_out_data until we *know* that the list is empty. | |
189 | * | |
190 | * Cleanup any flushed data buffers from the data list. Even in | |
191 | * abort mode, we want to flush this out as soon as possible. | |
192 | */ | |
193 | write_out_data: | |
194 | cond_resched(); | |
195 | spin_lock(&journal->j_list_lock); | |
196 | ||
197 | while (commit_transaction->t_sync_datalist) { | |
198 | jh = commit_transaction->t_sync_datalist; | |
199 | bh = jh2bh(jh); | |
200 | locked = 0; | |
201 | ||
202 | /* Get reference just to make sure buffer does not disappear | |
203 | * when we are forced to drop various locks */ | |
204 | get_bh(bh); | |
205 | /* If the buffer is dirty, we need to submit IO and hence | |
206 | * we need the buffer lock. We try to lock the buffer without | |
207 | * blocking. If we fail, we need to drop j_list_lock and do | |
208 | * blocking lock_buffer(). | |
209 | */ | |
210 | if (buffer_dirty(bh)) { | |
211 | if (test_set_buffer_locked(bh)) { | |
212 | BUFFER_TRACE(bh, "needs blocking lock"); | |
213 | spin_unlock(&journal->j_list_lock); | |
214 | /* Write out all data to prevent deadlocks */ | |
215 | journal_do_submit_data(wbuf, bufs); | |
216 | bufs = 0; | |
217 | lock_buffer(bh); | |
218 | spin_lock(&journal->j_list_lock); | |
219 | } | |
220 | locked = 1; | |
221 | } | |
222 | /* We have to get bh_state lock. Again out of order, sigh. */ | |
223 | if (!inverted_lock(journal, bh)) { | |
224 | jbd_lock_bh_state(bh); | |
225 | spin_lock(&journal->j_list_lock); | |
226 | } | |
227 | /* Someone already cleaned up the buffer? */ | |
228 | if (!buffer_jbd(bh) | |
229 | || jh->b_transaction != commit_transaction | |
230 | || jh->b_jlist != BJ_SyncData) { | |
231 | jbd_unlock_bh_state(bh); | |
232 | if (locked) | |
233 | unlock_buffer(bh); | |
234 | BUFFER_TRACE(bh, "already cleaned up"); | |
235 | put_bh(bh); | |
236 | continue; | |
237 | } | |
238 | if (locked && test_clear_buffer_dirty(bh)) { | |
239 | BUFFER_TRACE(bh, "needs writeout, adding to array"); | |
240 | wbuf[bufs++] = bh; | |
241 | __journal_file_buffer(jh, commit_transaction, | |
242 | BJ_Locked); | |
243 | jbd_unlock_bh_state(bh); | |
244 | if (bufs == journal->j_wbufsize) { | |
245 | spin_unlock(&journal->j_list_lock); | |
246 | journal_do_submit_data(wbuf, bufs); | |
247 | bufs = 0; | |
248 | goto write_out_data; | |
249 | } | |
6f5a9da1 HH |
250 | } else if (!locked && buffer_locked(bh)) { |
251 | __journal_file_buffer(jh, commit_transaction, | |
252 | BJ_Locked); | |
253 | jbd_unlock_bh_state(bh); | |
254 | put_bh(bh); | |
255 | } else { | |
3998b930 JK |
256 | BUFFER_TRACE(bh, "writeout complete: unfile"); |
257 | __journal_unfile_buffer(jh); | |
258 | jbd_unlock_bh_state(bh); | |
259 | if (locked) | |
260 | unlock_buffer(bh); | |
261 | journal_remove_journal_head(bh); | |
262 | /* Once for our safety reference, once for | |
263 | * journal_remove_journal_head() */ | |
264 | put_bh(bh); | |
265 | put_bh(bh); | |
266 | } | |
267 | ||
268 | if (lock_need_resched(&journal->j_list_lock)) { | |
269 | spin_unlock(&journal->j_list_lock); | |
270 | goto write_out_data; | |
271 | } | |
272 | } | |
273 | spin_unlock(&journal->j_list_lock); | |
274 | journal_do_submit_data(wbuf, bufs); | |
275 | } | |
276 | ||
1da177e4 LT |
277 | /* |
278 | * journal_commit_transaction | |
279 | * | |
280 | * The primary function for committing a transaction to the log. This | |
281 | * function is called by the journal thread to begin a complete commit. | |
282 | */ | |
283 | void journal_commit_transaction(journal_t *journal) | |
284 | { | |
285 | transaction_t *commit_transaction; | |
286 | struct journal_head *jh, *new_jh, *descriptor; | |
287 | struct buffer_head **wbuf = journal->j_wbuf; | |
288 | int bufs; | |
289 | int flags; | |
290 | int err; | |
291 | unsigned long blocknr; | |
292 | char *tagp = NULL; | |
293 | journal_header_t *header; | |
294 | journal_block_tag_t *tag = NULL; | |
295 | int space_left = 0; | |
296 | int first_tag = 0; | |
297 | int tag_flag; | |
298 | int i; | |
299 | ||
300 | /* | |
301 | * First job: lock down the current transaction and wait for | |
302 | * all outstanding updates to complete. | |
303 | */ | |
304 | ||
305 | #ifdef COMMIT_STATS | |
306 | spin_lock(&journal->j_list_lock); | |
307 | summarise_journal_usage(journal); | |
308 | spin_unlock(&journal->j_list_lock); | |
309 | #endif | |
310 | ||
311 | /* Do we need to erase the effects of a prior journal_flush? */ | |
312 | if (journal->j_flags & JFS_FLUSHED) { | |
313 | jbd_debug(3, "super block updated\n"); | |
314 | journal_update_superblock(journal, 1); | |
315 | } else { | |
316 | jbd_debug(3, "superblock not updated\n"); | |
317 | } | |
318 | ||
319 | J_ASSERT(journal->j_running_transaction != NULL); | |
320 | J_ASSERT(journal->j_committing_transaction == NULL); | |
321 | ||
322 | commit_transaction = journal->j_running_transaction; | |
323 | J_ASSERT(commit_transaction->t_state == T_RUNNING); | |
324 | ||
325 | jbd_debug(1, "JBD: starting commit of transaction %d\n", | |
326 | commit_transaction->t_tid); | |
327 | ||
328 | spin_lock(&journal->j_state_lock); | |
329 | commit_transaction->t_state = T_LOCKED; | |
330 | ||
331 | spin_lock(&commit_transaction->t_handle_lock); | |
332 | while (commit_transaction->t_updates) { | |
333 | DEFINE_WAIT(wait); | |
334 | ||
335 | prepare_to_wait(&journal->j_wait_updates, &wait, | |
336 | TASK_UNINTERRUPTIBLE); | |
337 | if (commit_transaction->t_updates) { | |
338 | spin_unlock(&commit_transaction->t_handle_lock); | |
339 | spin_unlock(&journal->j_state_lock); | |
340 | schedule(); | |
341 | spin_lock(&journal->j_state_lock); | |
342 | spin_lock(&commit_transaction->t_handle_lock); | |
343 | } | |
344 | finish_wait(&journal->j_wait_updates, &wait); | |
345 | } | |
346 | spin_unlock(&commit_transaction->t_handle_lock); | |
347 | ||
348 | J_ASSERT (commit_transaction->t_outstanding_credits <= | |
349 | journal->j_max_transaction_buffers); | |
350 | ||
351 | /* | |
352 | * First thing we are allowed to do is to discard any remaining | |
353 | * BJ_Reserved buffers. Note, it is _not_ permissible to assume | |
354 | * that there are no such buffers: if a large filesystem | |
355 | * operation like a truncate needs to split itself over multiple | |
356 | * transactions, then it may try to do a journal_restart() while | |
357 | * there are still BJ_Reserved buffers outstanding. These must | |
358 | * be released cleanly from the current transaction. | |
359 | * | |
360 | * In this case, the filesystem must still reserve write access | |
361 | * again before modifying the buffer in the new transaction, but | |
362 | * we do not require it to remember exactly which old buffers it | |
363 | * has reserved. This is consistent with the existing behaviour | |
364 | * that multiple journal_get_write_access() calls to the same | |
365 | * buffer are perfectly permissable. | |
366 | */ | |
367 | while (commit_transaction->t_reserved_list) { | |
368 | jh = commit_transaction->t_reserved_list; | |
369 | JBUFFER_TRACE(jh, "reserved, unused: refile"); | |
370 | /* | |
371 | * A journal_get_undo_access()+journal_release_buffer() may | |
372 | * leave undo-committed data. | |
373 | */ | |
374 | if (jh->b_committed_data) { | |
375 | struct buffer_head *bh = jh2bh(jh); | |
376 | ||
377 | jbd_lock_bh_state(bh); | |
ea817398 | 378 | jbd_slab_free(jh->b_committed_data, bh->b_size); |
f99d49ad | 379 | jh->b_committed_data = NULL; |
1da177e4 LT |
380 | jbd_unlock_bh_state(bh); |
381 | } | |
382 | journal_refile_buffer(journal, jh); | |
383 | } | |
384 | ||
385 | /* | |
386 | * Now try to drop any written-back buffers from the journal's | |
387 | * checkpoint lists. We do this *before* commit because it potentially | |
388 | * frees some memory | |
389 | */ | |
390 | spin_lock(&journal->j_list_lock); | |
391 | __journal_clean_checkpoint_list(journal); | |
392 | spin_unlock(&journal->j_list_lock); | |
393 | ||
394 | jbd_debug (3, "JBD: commit phase 1\n"); | |
395 | ||
396 | /* | |
397 | * Switch to a new revoke table. | |
398 | */ | |
399 | journal_switch_revoke_table(journal); | |
400 | ||
401 | commit_transaction->t_state = T_FLUSH; | |
402 | journal->j_committing_transaction = commit_transaction; | |
403 | journal->j_running_transaction = NULL; | |
404 | commit_transaction->t_log_start = journal->j_head; | |
405 | wake_up(&journal->j_wait_transaction_locked); | |
406 | spin_unlock(&journal->j_state_lock); | |
407 | ||
408 | jbd_debug (3, "JBD: commit phase 2\n"); | |
409 | ||
410 | /* | |
411 | * First, drop modified flag: all accesses to the buffers | |
412 | * will be tracked for a new trasaction only -bzzz | |
413 | */ | |
414 | spin_lock(&journal->j_list_lock); | |
415 | if (commit_transaction->t_buffers) { | |
416 | new_jh = jh = commit_transaction->t_buffers->b_tnext; | |
417 | do { | |
418 | J_ASSERT_JH(new_jh, new_jh->b_modified == 1 || | |
419 | new_jh->b_modified == 0); | |
420 | new_jh->b_modified = 0; | |
421 | new_jh = new_jh->b_tnext; | |
422 | } while (new_jh != jh); | |
423 | } | |
424 | spin_unlock(&journal->j_list_lock); | |
425 | ||
426 | /* | |
427 | * Now start flushing things to disk, in the order they appear | |
428 | * on the transaction lists. Data blocks go first. | |
429 | */ | |
1da177e4 | 430 | err = 0; |
3998b930 | 431 | journal_submit_data_buffers(journal, commit_transaction); |
1da177e4 LT |
432 | |
433 | /* | |
434 | * Wait for all previously submitted IO to complete. | |
435 | */ | |
3998b930 | 436 | spin_lock(&journal->j_list_lock); |
1da177e4 LT |
437 | while (commit_transaction->t_locked_list) { |
438 | struct buffer_head *bh; | |
439 | ||
440 | jh = commit_transaction->t_locked_list->b_tprev; | |
441 | bh = jh2bh(jh); | |
442 | get_bh(bh); | |
443 | if (buffer_locked(bh)) { | |
444 | spin_unlock(&journal->j_list_lock); | |
445 | wait_on_buffer(bh); | |
446 | if (unlikely(!buffer_uptodate(bh))) | |
447 | err = -EIO; | |
448 | spin_lock(&journal->j_list_lock); | |
449 | } | |
450 | if (!inverted_lock(journal, bh)) { | |
451 | put_bh(bh); | |
452 | spin_lock(&journal->j_list_lock); | |
453 | continue; | |
454 | } | |
455 | if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) { | |
456 | __journal_unfile_buffer(jh); | |
457 | jbd_unlock_bh_state(bh); | |
458 | journal_remove_journal_head(bh); | |
459 | put_bh(bh); | |
460 | } else { | |
461 | jbd_unlock_bh_state(bh); | |
462 | } | |
463 | put_bh(bh); | |
464 | cond_resched_lock(&journal->j_list_lock); | |
465 | } | |
466 | spin_unlock(&journal->j_list_lock); | |
467 | ||
468 | if (err) | |
469 | __journal_abort_hard(journal); | |
470 | ||
471 | journal_write_revoke_records(journal, commit_transaction); | |
472 | ||
473 | jbd_debug(3, "JBD: commit phase 2\n"); | |
474 | ||
475 | /* | |
476 | * If we found any dirty or locked buffers, then we should have | |
477 | * looped back up to the write_out_data label. If there weren't | |
478 | * any then journal_clean_data_list should have wiped the list | |
479 | * clean by now, so check that it is in fact empty. | |
480 | */ | |
481 | J_ASSERT (commit_transaction->t_sync_datalist == NULL); | |
482 | ||
483 | jbd_debug (3, "JBD: commit phase 3\n"); | |
484 | ||
485 | /* | |
486 | * Way to go: we have now written out all of the data for a | |
487 | * transaction! Now comes the tricky part: we need to write out | |
488 | * metadata. Loop over the transaction's entire buffer list: | |
489 | */ | |
490 | commit_transaction->t_state = T_COMMIT; | |
491 | ||
492 | descriptor = NULL; | |
493 | bufs = 0; | |
494 | while (commit_transaction->t_buffers) { | |
495 | ||
496 | /* Find the next buffer to be journaled... */ | |
497 | ||
498 | jh = commit_transaction->t_buffers; | |
499 | ||
500 | /* If we're in abort mode, we just un-journal the buffer and | |
501 | release it for background writing. */ | |
502 | ||
503 | if (is_journal_aborted(journal)) { | |
504 | JBUFFER_TRACE(jh, "journal is aborting: refile"); | |
505 | journal_refile_buffer(journal, jh); | |
506 | /* If that was the last one, we need to clean up | |
507 | * any descriptor buffers which may have been | |
508 | * already allocated, even if we are now | |
509 | * aborting. */ | |
510 | if (!commit_transaction->t_buffers) | |
511 | goto start_journal_io; | |
512 | continue; | |
513 | } | |
514 | ||
515 | /* Make sure we have a descriptor block in which to | |
516 | record the metadata buffer. */ | |
517 | ||
518 | if (!descriptor) { | |
519 | struct buffer_head *bh; | |
520 | ||
521 | J_ASSERT (bufs == 0); | |
522 | ||
523 | jbd_debug(4, "JBD: get descriptor\n"); | |
524 | ||
525 | descriptor = journal_get_descriptor_buffer(journal); | |
526 | if (!descriptor) { | |
527 | __journal_abort_hard(journal); | |
528 | continue; | |
529 | } | |
530 | ||
531 | bh = jh2bh(descriptor); | |
532 | jbd_debug(4, "JBD: got buffer %llu (%p)\n", | |
533 | (unsigned long long)bh->b_blocknr, bh->b_data); | |
534 | header = (journal_header_t *)&bh->b_data[0]; | |
535 | header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); | |
536 | header->h_blocktype = cpu_to_be32(JFS_DESCRIPTOR_BLOCK); | |
537 | header->h_sequence = cpu_to_be32(commit_transaction->t_tid); | |
538 | ||
539 | tagp = &bh->b_data[sizeof(journal_header_t)]; | |
540 | space_left = bh->b_size - sizeof(journal_header_t); | |
541 | first_tag = 1; | |
542 | set_buffer_jwrite(bh); | |
543 | set_buffer_dirty(bh); | |
544 | wbuf[bufs++] = bh; | |
545 | ||
546 | /* Record it so that we can wait for IO | |
547 | completion later */ | |
548 | BUFFER_TRACE(bh, "ph3: file as descriptor"); | |
549 | journal_file_buffer(descriptor, commit_transaction, | |
550 | BJ_LogCtl); | |
551 | } | |
552 | ||
553 | /* Where is the buffer to be written? */ | |
554 | ||
555 | err = journal_next_log_block(journal, &blocknr); | |
556 | /* If the block mapping failed, just abandon the buffer | |
557 | and repeat this loop: we'll fall into the | |
558 | refile-on-abort condition above. */ | |
559 | if (err) { | |
560 | __journal_abort_hard(journal); | |
561 | continue; | |
562 | } | |
563 | ||
564 | /* | |
565 | * start_this_handle() uses t_outstanding_credits to determine | |
566 | * the free space in the log, but this counter is changed | |
567 | * by journal_next_log_block() also. | |
568 | */ | |
569 | commit_transaction->t_outstanding_credits--; | |
570 | ||
571 | /* Bump b_count to prevent truncate from stumbling over | |
572 | the shadowed buffer! @@@ This can go if we ever get | |
573 | rid of the BJ_IO/BJ_Shadow pairing of buffers. */ | |
574 | atomic_inc(&jh2bh(jh)->b_count); | |
575 | ||
576 | /* Make a temporary IO buffer with which to write it out | |
577 | (this will requeue both the metadata buffer and the | |
578 | temporary IO buffer). new_bh goes on BJ_IO*/ | |
579 | ||
580 | set_bit(BH_JWrite, &jh2bh(jh)->b_state); | |
581 | /* | |
582 | * akpm: journal_write_metadata_buffer() sets | |
583 | * new_bh->b_transaction to commit_transaction. | |
584 | * We need to clean this up before we release new_bh | |
585 | * (which is of type BJ_IO) | |
586 | */ | |
587 | JBUFFER_TRACE(jh, "ph3: write metadata"); | |
588 | flags = journal_write_metadata_buffer(commit_transaction, | |
589 | jh, &new_jh, blocknr); | |
590 | set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); | |
591 | wbuf[bufs++] = jh2bh(new_jh); | |
592 | ||
593 | /* Record the new block's tag in the current descriptor | |
594 | buffer */ | |
595 | ||
596 | tag_flag = 0; | |
597 | if (flags & 1) | |
598 | tag_flag |= JFS_FLAG_ESCAPE; | |
599 | if (!first_tag) | |
600 | tag_flag |= JFS_FLAG_SAME_UUID; | |
601 | ||
602 | tag = (journal_block_tag_t *) tagp; | |
603 | tag->t_blocknr = cpu_to_be32(jh2bh(jh)->b_blocknr); | |
604 | tag->t_flags = cpu_to_be32(tag_flag); | |
605 | tagp += sizeof(journal_block_tag_t); | |
606 | space_left -= sizeof(journal_block_tag_t); | |
607 | ||
608 | if (first_tag) { | |
609 | memcpy (tagp, journal->j_uuid, 16); | |
610 | tagp += 16; | |
611 | space_left -= 16; | |
612 | first_tag = 0; | |
613 | } | |
614 | ||
615 | /* If there's no more to do, or if the descriptor is full, | |
616 | let the IO rip! */ | |
617 | ||
618 | if (bufs == journal->j_wbufsize || | |
619 | commit_transaction->t_buffers == NULL || | |
620 | space_left < sizeof(journal_block_tag_t) + 16) { | |
621 | ||
622 | jbd_debug(4, "JBD: Submit %d IOs\n", bufs); | |
623 | ||
624 | /* Write an end-of-descriptor marker before | |
625 | submitting the IOs. "tag" still points to | |
626 | the last tag we set up. */ | |
627 | ||
628 | tag->t_flags |= cpu_to_be32(JFS_FLAG_LAST_TAG); | |
629 | ||
630 | start_journal_io: | |
631 | for (i = 0; i < bufs; i++) { | |
632 | struct buffer_head *bh = wbuf[i]; | |
633 | lock_buffer(bh); | |
634 | clear_buffer_dirty(bh); | |
635 | set_buffer_uptodate(bh); | |
636 | bh->b_end_io = journal_end_buffer_io_sync; | |
637 | submit_bh(WRITE, bh); | |
638 | } | |
639 | cond_resched(); | |
640 | ||
641 | /* Force a new descriptor to be generated next | |
642 | time round the loop. */ | |
643 | descriptor = NULL; | |
644 | bufs = 0; | |
645 | } | |
646 | } | |
647 | ||
648 | /* Lo and behold: we have just managed to send a transaction to | |
649 | the log. Before we can commit it, wait for the IO so far to | |
650 | complete. Control buffers being written are on the | |
651 | transaction's t_log_list queue, and metadata buffers are on | |
652 | the t_iobuf_list queue. | |
653 | ||
654 | Wait for the buffers in reverse order. That way we are | |
655 | less likely to be woken up until all IOs have completed, and | |
656 | so we incur less scheduling load. | |
657 | */ | |
658 | ||
659 | jbd_debug(3, "JBD: commit phase 4\n"); | |
660 | ||
661 | /* | |
662 | * akpm: these are BJ_IO, and j_list_lock is not needed. | |
663 | * See __journal_try_to_free_buffer. | |
664 | */ | |
665 | wait_for_iobuf: | |
666 | while (commit_transaction->t_iobuf_list != NULL) { | |
667 | struct buffer_head *bh; | |
668 | ||
669 | jh = commit_transaction->t_iobuf_list->b_tprev; | |
670 | bh = jh2bh(jh); | |
671 | if (buffer_locked(bh)) { | |
672 | wait_on_buffer(bh); | |
673 | goto wait_for_iobuf; | |
674 | } | |
675 | if (cond_resched()) | |
676 | goto wait_for_iobuf; | |
677 | ||
678 | if (unlikely(!buffer_uptodate(bh))) | |
679 | err = -EIO; | |
680 | ||
681 | clear_buffer_jwrite(bh); | |
682 | ||
683 | JBUFFER_TRACE(jh, "ph4: unfile after journal write"); | |
684 | journal_unfile_buffer(journal, jh); | |
685 | ||
686 | /* | |
687 | * ->t_iobuf_list should contain only dummy buffer_heads | |
688 | * which were created by journal_write_metadata_buffer(). | |
689 | */ | |
690 | BUFFER_TRACE(bh, "dumping temporary bh"); | |
691 | journal_put_journal_head(jh); | |
692 | __brelse(bh); | |
693 | J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); | |
694 | free_buffer_head(bh); | |
695 | ||
696 | /* We also have to unlock and free the corresponding | |
697 | shadowed buffer */ | |
698 | jh = commit_transaction->t_shadow_list->b_tprev; | |
699 | bh = jh2bh(jh); | |
700 | clear_bit(BH_JWrite, &bh->b_state); | |
701 | J_ASSERT_BH(bh, buffer_jbddirty(bh)); | |
702 | ||
703 | /* The metadata is now released for reuse, but we need | |
704 | to remember it against this transaction so that when | |
705 | we finally commit, we can do any checkpointing | |
706 | required. */ | |
707 | JBUFFER_TRACE(jh, "file as BJ_Forget"); | |
708 | journal_file_buffer(jh, commit_transaction, BJ_Forget); | |
709 | /* Wake up any transactions which were waiting for this | |
710 | IO to complete */ | |
711 | wake_up_bit(&bh->b_state, BH_Unshadow); | |
712 | JBUFFER_TRACE(jh, "brelse shadowed buffer"); | |
713 | __brelse(bh); | |
714 | } | |
715 | ||
716 | J_ASSERT (commit_transaction->t_shadow_list == NULL); | |
717 | ||
718 | jbd_debug(3, "JBD: commit phase 5\n"); | |
719 | ||
720 | /* Here we wait for the revoke record and descriptor record buffers */ | |
721 | wait_for_ctlbuf: | |
722 | while (commit_transaction->t_log_list != NULL) { | |
723 | struct buffer_head *bh; | |
724 | ||
725 | jh = commit_transaction->t_log_list->b_tprev; | |
726 | bh = jh2bh(jh); | |
727 | if (buffer_locked(bh)) { | |
728 | wait_on_buffer(bh); | |
729 | goto wait_for_ctlbuf; | |
730 | } | |
731 | if (cond_resched()) | |
732 | goto wait_for_ctlbuf; | |
733 | ||
734 | if (unlikely(!buffer_uptodate(bh))) | |
735 | err = -EIO; | |
736 | ||
737 | BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); | |
738 | clear_buffer_jwrite(bh); | |
739 | journal_unfile_buffer(journal, jh); | |
740 | journal_put_journal_head(jh); | |
741 | __brelse(bh); /* One for getblk */ | |
742 | /* AKPM: bforget here */ | |
743 | } | |
744 | ||
745 | jbd_debug(3, "JBD: commit phase 6\n"); | |
746 | ||
747 | if (journal_write_commit_record(journal, commit_transaction)) | |
748 | err = -EIO; | |
749 | ||
750 | if (err) | |
751 | __journal_abort_hard(journal); | |
752 | ||
753 | /* End of a transaction! Finally, we can do checkpoint | |
754 | processing: any buffers committed as a result of this | |
755 | transaction can be removed from any checkpoint list it was on | |
756 | before. */ | |
757 | ||
758 | jbd_debug(3, "JBD: commit phase 7\n"); | |
759 | ||
760 | J_ASSERT(commit_transaction->t_sync_datalist == NULL); | |
761 | J_ASSERT(commit_transaction->t_buffers == NULL); | |
762 | J_ASSERT(commit_transaction->t_checkpoint_list == NULL); | |
763 | J_ASSERT(commit_transaction->t_iobuf_list == NULL); | |
764 | J_ASSERT(commit_transaction->t_shadow_list == NULL); | |
765 | J_ASSERT(commit_transaction->t_log_list == NULL); | |
766 | ||
767 | restart_loop: | |
e6c9f5c1 JK |
768 | /* |
769 | * As there are other places (journal_unmap_buffer()) adding buffers | |
770 | * to this list we have to be careful and hold the j_list_lock. | |
771 | */ | |
772 | spin_lock(&journal->j_list_lock); | |
1da177e4 LT |
773 | while (commit_transaction->t_forget) { |
774 | transaction_t *cp_transaction; | |
775 | struct buffer_head *bh; | |
776 | ||
777 | jh = commit_transaction->t_forget; | |
e6c9f5c1 | 778 | spin_unlock(&journal->j_list_lock); |
1da177e4 LT |
779 | bh = jh2bh(jh); |
780 | jbd_lock_bh_state(bh); | |
781 | J_ASSERT_JH(jh, jh->b_transaction == commit_transaction || | |
782 | jh->b_transaction == journal->j_running_transaction); | |
783 | ||
784 | /* | |
785 | * If there is undo-protected committed data against | |
786 | * this buffer, then we can remove it now. If it is a | |
787 | * buffer needing such protection, the old frozen_data | |
788 | * field now points to a committed version of the | |
789 | * buffer, so rotate that field to the new committed | |
790 | * data. | |
791 | * | |
792 | * Otherwise, we can just throw away the frozen data now. | |
793 | */ | |
794 | if (jh->b_committed_data) { | |
ea817398 | 795 | jbd_slab_free(jh->b_committed_data, bh->b_size); |
1da177e4 LT |
796 | jh->b_committed_data = NULL; |
797 | if (jh->b_frozen_data) { | |
798 | jh->b_committed_data = jh->b_frozen_data; | |
799 | jh->b_frozen_data = NULL; | |
800 | } | |
801 | } else if (jh->b_frozen_data) { | |
ea817398 | 802 | jbd_slab_free(jh->b_frozen_data, bh->b_size); |
1da177e4 LT |
803 | jh->b_frozen_data = NULL; |
804 | } | |
805 | ||
806 | spin_lock(&journal->j_list_lock); | |
807 | cp_transaction = jh->b_cp_transaction; | |
808 | if (cp_transaction) { | |
809 | JBUFFER_TRACE(jh, "remove from old cp transaction"); | |
810 | __journal_remove_checkpoint(jh); | |
811 | } | |
812 | ||
813 | /* Only re-checkpoint the buffer_head if it is marked | |
814 | * dirty. If the buffer was added to the BJ_Forget list | |
815 | * by journal_forget, it may no longer be dirty and | |
816 | * there's no point in keeping a checkpoint record for | |
817 | * it. */ | |
818 | ||
819 | /* A buffer which has been freed while still being | |
820 | * journaled by a previous transaction may end up still | |
821 | * being dirty here, but we want to avoid writing back | |
822 | * that buffer in the future now that the last use has | |
823 | * been committed. That's not only a performance gain, | |
824 | * it also stops aliasing problems if the buffer is left | |
825 | * behind for writeback and gets reallocated for another | |
826 | * use in a different page. */ | |
827 | if (buffer_freed(bh)) { | |
828 | clear_buffer_freed(bh); | |
829 | clear_buffer_jbddirty(bh); | |
830 | } | |
831 | ||
832 | if (buffer_jbddirty(bh)) { | |
833 | JBUFFER_TRACE(jh, "add to new checkpointing trans"); | |
834 | __journal_insert_checkpoint(jh, commit_transaction); | |
835 | JBUFFER_TRACE(jh, "refile for checkpoint writeback"); | |
836 | __journal_refile_buffer(jh); | |
837 | jbd_unlock_bh_state(bh); | |
838 | } else { | |
839 | J_ASSERT_BH(bh, !buffer_dirty(bh)); | |
9ada7340 JK |
840 | /* The buffer on BJ_Forget list and not jbddirty means |
841 | * it has been freed by this transaction and hence it | |
842 | * could not have been reallocated until this | |
843 | * transaction has committed. *BUT* it could be | |
844 | * reallocated once we have written all the data to | |
845 | * disk and before we process the buffer on BJ_Forget | |
846 | * list. */ | |
847 | JBUFFER_TRACE(jh, "refile or unfile freed buffer"); | |
848 | __journal_refile_buffer(jh); | |
849 | if (!jh->b_transaction) { | |
850 | jbd_unlock_bh_state(bh); | |
851 | /* needs a brelse */ | |
852 | journal_remove_journal_head(bh); | |
853 | release_buffer_page(bh); | |
854 | } else | |
855 | jbd_unlock_bh_state(bh); | |
1da177e4 | 856 | } |
e6c9f5c1 JK |
857 | cond_resched_lock(&journal->j_list_lock); |
858 | } | |
859 | spin_unlock(&journal->j_list_lock); | |
860 | /* | |
861 | * This is a bit sleazy. We borrow j_list_lock to protect | |
862 | * journal->j_committing_transaction in __journal_remove_checkpoint. | |
863 | * Really, __journal_remove_checkpoint should be using j_state_lock but | |
864 | * it's a bit hassle to hold that across __journal_remove_checkpoint | |
865 | */ | |
866 | spin_lock(&journal->j_state_lock); | |
867 | spin_lock(&journal->j_list_lock); | |
868 | /* | |
869 | * Now recheck if some buffers did not get attached to the transaction | |
870 | * while the lock was dropped... | |
871 | */ | |
872 | if (commit_transaction->t_forget) { | |
1da177e4 | 873 | spin_unlock(&journal->j_list_lock); |
e6c9f5c1 JK |
874 | spin_unlock(&journal->j_state_lock); |
875 | goto restart_loop; | |
1da177e4 LT |
876 | } |
877 | ||
878 | /* Done with this transaction! */ | |
879 | ||
880 | jbd_debug(3, "JBD: commit phase 8\n"); | |
881 | ||
882 | J_ASSERT(commit_transaction->t_state == T_COMMIT); | |
883 | ||
1da177e4 LT |
884 | commit_transaction->t_state = T_FINISHED; |
885 | J_ASSERT(commit_transaction == journal->j_committing_transaction); | |
886 | journal->j_commit_sequence = commit_transaction->t_tid; | |
887 | journal->j_committing_transaction = NULL; | |
888 | spin_unlock(&journal->j_state_lock); | |
889 | ||
7c8903f6 | 890 | if (commit_transaction->t_checkpoint_list == NULL) { |
1da177e4 LT |
891 | __journal_drop_transaction(journal, commit_transaction); |
892 | } else { | |
893 | if (journal->j_checkpoint_transactions == NULL) { | |
894 | journal->j_checkpoint_transactions = commit_transaction; | |
895 | commit_transaction->t_cpnext = commit_transaction; | |
896 | commit_transaction->t_cpprev = commit_transaction; | |
897 | } else { | |
898 | commit_transaction->t_cpnext = | |
899 | journal->j_checkpoint_transactions; | |
900 | commit_transaction->t_cpprev = | |
901 | commit_transaction->t_cpnext->t_cpprev; | |
902 | commit_transaction->t_cpnext->t_cpprev = | |
903 | commit_transaction; | |
904 | commit_transaction->t_cpprev->t_cpnext = | |
905 | commit_transaction; | |
906 | } | |
907 | } | |
908 | spin_unlock(&journal->j_list_lock); | |
909 | ||
910 | jbd_debug(1, "JBD: commit %d complete, head %d\n", | |
911 | journal->j_commit_sequence, journal->j_tail_sequence); | |
912 | ||
913 | wake_up(&journal->j_wait_done_commit); | |
914 | } |