Commit | Line | Data |
---|---|---|
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; | |
5315217e JK |
107 | journal_header_t *header; |
108 | int ret; | |
1da177e4 LT |
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 | ||
5315217e JK |
120 | header = (journal_header_t *)(bh->b_data); |
121 | header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); | |
122 | header->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK); | |
123 | header->h_sequence = cpu_to_be32(commit_transaction->t_tid); | |
1da177e4 LT |
124 | |
125 | JBUFFER_TRACE(descriptor, "write commit block"); | |
126 | set_buffer_dirty(bh); | |
127 | if (journal->j_flags & JFS_BARRIER) { | |
128 | set_buffer_ordered(bh); | |
129 | barrier_done = 1; | |
130 | } | |
131 | ret = sync_dirty_buffer(bh); | |
28ae094c NB |
132 | if (barrier_done) |
133 | clear_buffer_ordered(bh); | |
1da177e4 LT |
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 */ | |
1da177e4 LT |
151 | set_buffer_uptodate(bh); |
152 | set_buffer_dirty(bh); | |
153 | ret = sync_dirty_buffer(bh); | |
154 | } | |
155 | put_bh(bh); /* One for getblk() */ | |
156 | journal_put_journal_head(descriptor); | |
157 | ||
158 | return (ret == -EIO); | |
159 | } | |
160 | ||
3998b930 JK |
161 | static void journal_do_submit_data(struct buffer_head **wbuf, int bufs) |
162 | { | |
163 | int i; | |
164 | ||
165 | for (i = 0; i < bufs; i++) { | |
166 | wbuf[i]->b_end_io = end_buffer_write_sync; | |
167 | /* We use-up our safety reference in submit_bh() */ | |
168 | submit_bh(WRITE, wbuf[i]); | |
169 | } | |
170 | } | |
171 | ||
172 | /* | |
173 | * Submit all the data buffers to disk | |
174 | */ | |
175 | static void journal_submit_data_buffers(journal_t *journal, | |
176 | transaction_t *commit_transaction) | |
177 | { | |
178 | struct journal_head *jh; | |
179 | struct buffer_head *bh; | |
180 | int locked; | |
181 | int bufs = 0; | |
182 | struct buffer_head **wbuf = journal->j_wbuf; | |
183 | ||
184 | /* | |
185 | * Whenever we unlock the journal and sleep, things can get added | |
186 | * onto ->t_sync_datalist, so we have to keep looping back to | |
187 | * write_out_data until we *know* that the list is empty. | |
188 | * | |
189 | * Cleanup any flushed data buffers from the data list. Even in | |
190 | * abort mode, we want to flush this out as soon as possible. | |
191 | */ | |
192 | write_out_data: | |
193 | cond_resched(); | |
194 | spin_lock(&journal->j_list_lock); | |
195 | ||
196 | while (commit_transaction->t_sync_datalist) { | |
197 | jh = commit_transaction->t_sync_datalist; | |
198 | bh = jh2bh(jh); | |
199 | locked = 0; | |
200 | ||
201 | /* Get reference just to make sure buffer does not disappear | |
202 | * when we are forced to drop various locks */ | |
203 | get_bh(bh); | |
204 | /* If the buffer is dirty, we need to submit IO and hence | |
205 | * we need the buffer lock. We try to lock the buffer without | |
206 | * blocking. If we fail, we need to drop j_list_lock and do | |
207 | * blocking lock_buffer(). | |
208 | */ | |
209 | if (buffer_dirty(bh)) { | |
210 | if (test_set_buffer_locked(bh)) { | |
211 | BUFFER_TRACE(bh, "needs blocking lock"); | |
212 | spin_unlock(&journal->j_list_lock); | |
213 | /* Write out all data to prevent deadlocks */ | |
214 | journal_do_submit_data(wbuf, bufs); | |
215 | bufs = 0; | |
216 | lock_buffer(bh); | |
217 | spin_lock(&journal->j_list_lock); | |
218 | } | |
219 | locked = 1; | |
220 | } | |
221 | /* We have to get bh_state lock. Again out of order, sigh. */ | |
222 | if (!inverted_lock(journal, bh)) { | |
223 | jbd_lock_bh_state(bh); | |
224 | spin_lock(&journal->j_list_lock); | |
225 | } | |
226 | /* Someone already cleaned up the buffer? */ | |
227 | if (!buffer_jbd(bh) | |
228 | || jh->b_transaction != commit_transaction | |
229 | || jh->b_jlist != BJ_SyncData) { | |
230 | jbd_unlock_bh_state(bh); | |
231 | if (locked) | |
232 | unlock_buffer(bh); | |
233 | BUFFER_TRACE(bh, "already cleaned up"); | |
234 | put_bh(bh); | |
235 | continue; | |
236 | } | |
237 | if (locked && test_clear_buffer_dirty(bh)) { | |
238 | BUFFER_TRACE(bh, "needs writeout, adding to array"); | |
239 | wbuf[bufs++] = bh; | |
240 | __journal_file_buffer(jh, commit_transaction, | |
241 | BJ_Locked); | |
242 | jbd_unlock_bh_state(bh); | |
243 | if (bufs == journal->j_wbufsize) { | |
244 | spin_unlock(&journal->j_list_lock); | |
245 | journal_do_submit_data(wbuf, bufs); | |
246 | bufs = 0; | |
247 | goto write_out_data; | |
248 | } | |
6f5a9da1 HH |
249 | } else if (!locked && buffer_locked(bh)) { |
250 | __journal_file_buffer(jh, commit_transaction, | |
251 | BJ_Locked); | |
252 | jbd_unlock_bh_state(bh); | |
253 | put_bh(bh); | |
254 | } else { | |
3998b930 JK |
255 | BUFFER_TRACE(bh, "writeout complete: unfile"); |
256 | __journal_unfile_buffer(jh); | |
257 | jbd_unlock_bh_state(bh); | |
258 | if (locked) | |
259 | unlock_buffer(bh); | |
260 | journal_remove_journal_head(bh); | |
261 | /* Once for our safety reference, once for | |
262 | * journal_remove_journal_head() */ | |
263 | put_bh(bh); | |
264 | put_bh(bh); | |
265 | } | |
266 | ||
95c354fe | 267 | if (need_resched() || spin_needbreak(&journal->j_list_lock)) { |
3998b930 JK |
268 | spin_unlock(&journal->j_list_lock); |
269 | goto write_out_data; | |
270 | } | |
271 | } | |
272 | spin_unlock(&journal->j_list_lock); | |
273 | journal_do_submit_data(wbuf, bufs); | |
274 | } | |
275 | ||
1da177e4 LT |
276 | /* |
277 | * journal_commit_transaction | |
278 | * | |
279 | * The primary function for committing a transaction to the log. This | |
280 | * function is called by the journal thread to begin a complete commit. | |
281 | */ | |
282 | void journal_commit_transaction(journal_t *journal) | |
283 | { | |
284 | transaction_t *commit_transaction; | |
285 | struct journal_head *jh, *new_jh, *descriptor; | |
286 | struct buffer_head **wbuf = journal->j_wbuf; | |
287 | int bufs; | |
288 | int flags; | |
289 | int err; | |
290 | unsigned long blocknr; | |
291 | char *tagp = NULL; | |
292 | journal_header_t *header; | |
293 | journal_block_tag_t *tag = NULL; | |
294 | int space_left = 0; | |
295 | int first_tag = 0; | |
296 | int tag_flag; | |
297 | int i; | |
298 | ||
299 | /* | |
300 | * First job: lock down the current transaction and wait for | |
301 | * all outstanding updates to complete. | |
302 | */ | |
303 | ||
304 | #ifdef COMMIT_STATS | |
305 | spin_lock(&journal->j_list_lock); | |
306 | summarise_journal_usage(journal); | |
307 | spin_unlock(&journal->j_list_lock); | |
308 | #endif | |
309 | ||
310 | /* Do we need to erase the effects of a prior journal_flush? */ | |
311 | if (journal->j_flags & JFS_FLUSHED) { | |
312 | jbd_debug(3, "super block updated\n"); | |
313 | journal_update_superblock(journal, 1); | |
314 | } else { | |
315 | jbd_debug(3, "superblock not updated\n"); | |
316 | } | |
317 | ||
318 | J_ASSERT(journal->j_running_transaction != NULL); | |
319 | J_ASSERT(journal->j_committing_transaction == NULL); | |
320 | ||
321 | commit_transaction = journal->j_running_transaction; | |
322 | J_ASSERT(commit_transaction->t_state == T_RUNNING); | |
323 | ||
324 | jbd_debug(1, "JBD: starting commit of transaction %d\n", | |
325 | commit_transaction->t_tid); | |
326 | ||
327 | spin_lock(&journal->j_state_lock); | |
328 | commit_transaction->t_state = T_LOCKED; | |
329 | ||
330 | spin_lock(&commit_transaction->t_handle_lock); | |
331 | while (commit_transaction->t_updates) { | |
332 | DEFINE_WAIT(wait); | |
333 | ||
334 | prepare_to_wait(&journal->j_wait_updates, &wait, | |
335 | TASK_UNINTERRUPTIBLE); | |
336 | if (commit_transaction->t_updates) { | |
337 | spin_unlock(&commit_transaction->t_handle_lock); | |
338 | spin_unlock(&journal->j_state_lock); | |
339 | schedule(); | |
340 | spin_lock(&journal->j_state_lock); | |
341 | spin_lock(&commit_transaction->t_handle_lock); | |
342 | } | |
343 | finish_wait(&journal->j_wait_updates, &wait); | |
344 | } | |
345 | spin_unlock(&commit_transaction->t_handle_lock); | |
346 | ||
347 | J_ASSERT (commit_transaction->t_outstanding_credits <= | |
348 | journal->j_max_transaction_buffers); | |
349 | ||
350 | /* | |
351 | * First thing we are allowed to do is to discard any remaining | |
352 | * BJ_Reserved buffers. Note, it is _not_ permissible to assume | |
353 | * that there are no such buffers: if a large filesystem | |
354 | * operation like a truncate needs to split itself over multiple | |
355 | * transactions, then it may try to do a journal_restart() while | |
356 | * there are still BJ_Reserved buffers outstanding. These must | |
357 | * be released cleanly from the current transaction. | |
358 | * | |
359 | * In this case, the filesystem must still reserve write access | |
360 | * again before modifying the buffer in the new transaction, but | |
361 | * we do not require it to remember exactly which old buffers it | |
362 | * has reserved. This is consistent with the existing behaviour | |
363 | * that multiple journal_get_write_access() calls to the same | |
364 | * buffer are perfectly permissable. | |
365 | */ | |
366 | while (commit_transaction->t_reserved_list) { | |
367 | jh = commit_transaction->t_reserved_list; | |
368 | JBUFFER_TRACE(jh, "reserved, unused: refile"); | |
369 | /* | |
370 | * A journal_get_undo_access()+journal_release_buffer() may | |
371 | * leave undo-committed data. | |
372 | */ | |
373 | if (jh->b_committed_data) { | |
374 | struct buffer_head *bh = jh2bh(jh); | |
375 | ||
376 | jbd_lock_bh_state(bh); | |
c089d490 | 377 | jbd_free(jh->b_committed_data, bh->b_size); |
f99d49ad | 378 | jh->b_committed_data = NULL; |
1da177e4 LT |
379 | jbd_unlock_bh_state(bh); |
380 | } | |
381 | journal_refile_buffer(journal, jh); | |
382 | } | |
383 | ||
384 | /* | |
385 | * Now try to drop any written-back buffers from the journal's | |
386 | * checkpoint lists. We do this *before* commit because it potentially | |
387 | * frees some memory | |
388 | */ | |
389 | spin_lock(&journal->j_list_lock); | |
390 | __journal_clean_checkpoint_list(journal); | |
391 | spin_unlock(&journal->j_list_lock); | |
392 | ||
393 | jbd_debug (3, "JBD: commit phase 1\n"); | |
394 | ||
395 | /* | |
396 | * Switch to a new revoke table. | |
397 | */ | |
398 | journal_switch_revoke_table(journal); | |
399 | ||
400 | commit_transaction->t_state = T_FLUSH; | |
401 | journal->j_committing_transaction = commit_transaction; | |
402 | journal->j_running_transaction = NULL; | |
403 | commit_transaction->t_log_start = journal->j_head; | |
404 | wake_up(&journal->j_wait_transaction_locked); | |
405 | spin_unlock(&journal->j_state_lock); | |
406 | ||
407 | jbd_debug (3, "JBD: commit phase 2\n"); | |
408 | ||
1da177e4 LT |
409 | /* |
410 | * Now start flushing things to disk, in the order they appear | |
411 | * on the transaction lists. Data blocks go first. | |
412 | */ | |
1da177e4 | 413 | err = 0; |
3998b930 | 414 | journal_submit_data_buffers(journal, commit_transaction); |
1da177e4 LT |
415 | |
416 | /* | |
417 | * Wait for all previously submitted IO to complete. | |
418 | */ | |
3998b930 | 419 | spin_lock(&journal->j_list_lock); |
1da177e4 LT |
420 | while (commit_transaction->t_locked_list) { |
421 | struct buffer_head *bh; | |
422 | ||
423 | jh = commit_transaction->t_locked_list->b_tprev; | |
424 | bh = jh2bh(jh); | |
425 | get_bh(bh); | |
426 | if (buffer_locked(bh)) { | |
427 | spin_unlock(&journal->j_list_lock); | |
428 | wait_on_buffer(bh); | |
429 | if (unlikely(!buffer_uptodate(bh))) | |
430 | err = -EIO; | |
431 | spin_lock(&journal->j_list_lock); | |
432 | } | |
433 | if (!inverted_lock(journal, bh)) { | |
434 | put_bh(bh); | |
435 | spin_lock(&journal->j_list_lock); | |
436 | continue; | |
437 | } | |
438 | if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) { | |
439 | __journal_unfile_buffer(jh); | |
440 | jbd_unlock_bh_state(bh); | |
441 | journal_remove_journal_head(bh); | |
442 | put_bh(bh); | |
443 | } else { | |
444 | jbd_unlock_bh_state(bh); | |
445 | } | |
446 | put_bh(bh); | |
447 | cond_resched_lock(&journal->j_list_lock); | |
448 | } | |
449 | spin_unlock(&journal->j_list_lock); | |
450 | ||
451 | if (err) | |
7a266e75 | 452 | journal_abort(journal, err); |
1da177e4 LT |
453 | |
454 | journal_write_revoke_records(journal, commit_transaction); | |
455 | ||
456 | jbd_debug(3, "JBD: commit phase 2\n"); | |
457 | ||
458 | /* | |
459 | * If we found any dirty or locked buffers, then we should have | |
460 | * looped back up to the write_out_data label. If there weren't | |
461 | * any then journal_clean_data_list should have wiped the list | |
462 | * clean by now, so check that it is in fact empty. | |
463 | */ | |
464 | J_ASSERT (commit_transaction->t_sync_datalist == NULL); | |
465 | ||
466 | jbd_debug (3, "JBD: commit phase 3\n"); | |
467 | ||
468 | /* | |
469 | * Way to go: we have now written out all of the data for a | |
470 | * transaction! Now comes the tricky part: we need to write out | |
471 | * metadata. Loop over the transaction's entire buffer list: | |
472 | */ | |
772279c5 | 473 | spin_lock(&journal->j_state_lock); |
1da177e4 | 474 | commit_transaction->t_state = T_COMMIT; |
772279c5 | 475 | spin_unlock(&journal->j_state_lock); |
1da177e4 | 476 | |
5b9a499d JB |
477 | J_ASSERT(commit_transaction->t_nr_buffers <= |
478 | commit_transaction->t_outstanding_credits); | |
479 | ||
1da177e4 LT |
480 | descriptor = NULL; |
481 | bufs = 0; | |
482 | while (commit_transaction->t_buffers) { | |
483 | ||
484 | /* Find the next buffer to be journaled... */ | |
485 | ||
486 | jh = commit_transaction->t_buffers; | |
487 | ||
488 | /* If we're in abort mode, we just un-journal the buffer and | |
489 | release it for background writing. */ | |
490 | ||
491 | if (is_journal_aborted(journal)) { | |
492 | JBUFFER_TRACE(jh, "journal is aborting: refile"); | |
493 | journal_refile_buffer(journal, jh); | |
494 | /* If that was the last one, we need to clean up | |
495 | * any descriptor buffers which may have been | |
496 | * already allocated, even if we are now | |
497 | * aborting. */ | |
498 | if (!commit_transaction->t_buffers) | |
499 | goto start_journal_io; | |
500 | continue; | |
501 | } | |
502 | ||
503 | /* Make sure we have a descriptor block in which to | |
504 | record the metadata buffer. */ | |
505 | ||
506 | if (!descriptor) { | |
507 | struct buffer_head *bh; | |
508 | ||
509 | J_ASSERT (bufs == 0); | |
510 | ||
511 | jbd_debug(4, "JBD: get descriptor\n"); | |
512 | ||
513 | descriptor = journal_get_descriptor_buffer(journal); | |
514 | if (!descriptor) { | |
7a266e75 | 515 | journal_abort(journal, -EIO); |
1da177e4 LT |
516 | continue; |
517 | } | |
518 | ||
519 | bh = jh2bh(descriptor); | |
520 | jbd_debug(4, "JBD: got buffer %llu (%p)\n", | |
521 | (unsigned long long)bh->b_blocknr, bh->b_data); | |
522 | header = (journal_header_t *)&bh->b_data[0]; | |
523 | header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); | |
524 | header->h_blocktype = cpu_to_be32(JFS_DESCRIPTOR_BLOCK); | |
525 | header->h_sequence = cpu_to_be32(commit_transaction->t_tid); | |
526 | ||
527 | tagp = &bh->b_data[sizeof(journal_header_t)]; | |
528 | space_left = bh->b_size - sizeof(journal_header_t); | |
529 | first_tag = 1; | |
530 | set_buffer_jwrite(bh); | |
531 | set_buffer_dirty(bh); | |
532 | wbuf[bufs++] = bh; | |
533 | ||
534 | /* Record it so that we can wait for IO | |
535 | completion later */ | |
536 | BUFFER_TRACE(bh, "ph3: file as descriptor"); | |
537 | journal_file_buffer(descriptor, commit_transaction, | |
538 | BJ_LogCtl); | |
539 | } | |
540 | ||
541 | /* Where is the buffer to be written? */ | |
542 | ||
543 | err = journal_next_log_block(journal, &blocknr); | |
544 | /* If the block mapping failed, just abandon the buffer | |
545 | and repeat this loop: we'll fall into the | |
546 | refile-on-abort condition above. */ | |
547 | if (err) { | |
7a266e75 | 548 | journal_abort(journal, err); |
1da177e4 LT |
549 | continue; |
550 | } | |
551 | ||
552 | /* | |
553 | * start_this_handle() uses t_outstanding_credits to determine | |
554 | * the free space in the log, but this counter is changed | |
555 | * by journal_next_log_block() also. | |
556 | */ | |
557 | commit_transaction->t_outstanding_credits--; | |
558 | ||
559 | /* Bump b_count to prevent truncate from stumbling over | |
560 | the shadowed buffer! @@@ This can go if we ever get | |
561 | rid of the BJ_IO/BJ_Shadow pairing of buffers. */ | |
562 | atomic_inc(&jh2bh(jh)->b_count); | |
563 | ||
564 | /* Make a temporary IO buffer with which to write it out | |
565 | (this will requeue both the metadata buffer and the | |
566 | temporary IO buffer). new_bh goes on BJ_IO*/ | |
567 | ||
568 | set_bit(BH_JWrite, &jh2bh(jh)->b_state); | |
569 | /* | |
570 | * akpm: journal_write_metadata_buffer() sets | |
571 | * new_bh->b_transaction to commit_transaction. | |
572 | * We need to clean this up before we release new_bh | |
573 | * (which is of type BJ_IO) | |
574 | */ | |
575 | JBUFFER_TRACE(jh, "ph3: write metadata"); | |
576 | flags = journal_write_metadata_buffer(commit_transaction, | |
577 | jh, &new_jh, blocknr); | |
578 | set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); | |
579 | wbuf[bufs++] = jh2bh(new_jh); | |
580 | ||
581 | /* Record the new block's tag in the current descriptor | |
582 | buffer */ | |
583 | ||
584 | tag_flag = 0; | |
585 | if (flags & 1) | |
586 | tag_flag |= JFS_FLAG_ESCAPE; | |
587 | if (!first_tag) | |
588 | tag_flag |= JFS_FLAG_SAME_UUID; | |
589 | ||
590 | tag = (journal_block_tag_t *) tagp; | |
591 | tag->t_blocknr = cpu_to_be32(jh2bh(jh)->b_blocknr); | |
592 | tag->t_flags = cpu_to_be32(tag_flag); | |
593 | tagp += sizeof(journal_block_tag_t); | |
594 | space_left -= sizeof(journal_block_tag_t); | |
595 | ||
596 | if (first_tag) { | |
597 | memcpy (tagp, journal->j_uuid, 16); | |
598 | tagp += 16; | |
599 | space_left -= 16; | |
600 | first_tag = 0; | |
601 | } | |
602 | ||
603 | /* If there's no more to do, or if the descriptor is full, | |
604 | let the IO rip! */ | |
605 | ||
606 | if (bufs == journal->j_wbufsize || | |
607 | commit_transaction->t_buffers == NULL || | |
608 | space_left < sizeof(journal_block_tag_t) + 16) { | |
609 | ||
610 | jbd_debug(4, "JBD: Submit %d IOs\n", bufs); | |
611 | ||
612 | /* Write an end-of-descriptor marker before | |
613 | submitting the IOs. "tag" still points to | |
614 | the last tag we set up. */ | |
615 | ||
616 | tag->t_flags |= cpu_to_be32(JFS_FLAG_LAST_TAG); | |
617 | ||
618 | start_journal_io: | |
619 | for (i = 0; i < bufs; i++) { | |
620 | struct buffer_head *bh = wbuf[i]; | |
621 | lock_buffer(bh); | |
622 | clear_buffer_dirty(bh); | |
623 | set_buffer_uptodate(bh); | |
624 | bh->b_end_io = journal_end_buffer_io_sync; | |
625 | submit_bh(WRITE, bh); | |
626 | } | |
627 | cond_resched(); | |
628 | ||
629 | /* Force a new descriptor to be generated next | |
630 | time round the loop. */ | |
631 | descriptor = NULL; | |
632 | bufs = 0; | |
633 | } | |
634 | } | |
635 | ||
636 | /* Lo and behold: we have just managed to send a transaction to | |
637 | the log. Before we can commit it, wait for the IO so far to | |
638 | complete. Control buffers being written are on the | |
639 | transaction's t_log_list queue, and metadata buffers are on | |
640 | the t_iobuf_list queue. | |
641 | ||
642 | Wait for the buffers in reverse order. That way we are | |
643 | less likely to be woken up until all IOs have completed, and | |
644 | so we incur less scheduling load. | |
645 | */ | |
646 | ||
647 | jbd_debug(3, "JBD: commit phase 4\n"); | |
648 | ||
649 | /* | |
650 | * akpm: these are BJ_IO, and j_list_lock is not needed. | |
651 | * See __journal_try_to_free_buffer. | |
652 | */ | |
653 | wait_for_iobuf: | |
654 | while (commit_transaction->t_iobuf_list != NULL) { | |
655 | struct buffer_head *bh; | |
656 | ||
657 | jh = commit_transaction->t_iobuf_list->b_tprev; | |
658 | bh = jh2bh(jh); | |
659 | if (buffer_locked(bh)) { | |
660 | wait_on_buffer(bh); | |
661 | goto wait_for_iobuf; | |
662 | } | |
663 | if (cond_resched()) | |
664 | goto wait_for_iobuf; | |
665 | ||
666 | if (unlikely(!buffer_uptodate(bh))) | |
667 | err = -EIO; | |
668 | ||
669 | clear_buffer_jwrite(bh); | |
670 | ||
671 | JBUFFER_TRACE(jh, "ph4: unfile after journal write"); | |
672 | journal_unfile_buffer(journal, jh); | |
673 | ||
674 | /* | |
675 | * ->t_iobuf_list should contain only dummy buffer_heads | |
676 | * which were created by journal_write_metadata_buffer(). | |
677 | */ | |
678 | BUFFER_TRACE(bh, "dumping temporary bh"); | |
679 | journal_put_journal_head(jh); | |
680 | __brelse(bh); | |
681 | J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); | |
682 | free_buffer_head(bh); | |
683 | ||
684 | /* We also have to unlock and free the corresponding | |
685 | shadowed buffer */ | |
686 | jh = commit_transaction->t_shadow_list->b_tprev; | |
687 | bh = jh2bh(jh); | |
688 | clear_bit(BH_JWrite, &bh->b_state); | |
689 | J_ASSERT_BH(bh, buffer_jbddirty(bh)); | |
690 | ||
691 | /* The metadata is now released for reuse, but we need | |
692 | to remember it against this transaction so that when | |
693 | we finally commit, we can do any checkpointing | |
694 | required. */ | |
695 | JBUFFER_TRACE(jh, "file as BJ_Forget"); | |
696 | journal_file_buffer(jh, commit_transaction, BJ_Forget); | |
697 | /* Wake up any transactions which were waiting for this | |
698 | IO to complete */ | |
699 | wake_up_bit(&bh->b_state, BH_Unshadow); | |
700 | JBUFFER_TRACE(jh, "brelse shadowed buffer"); | |
701 | __brelse(bh); | |
702 | } | |
703 | ||
704 | J_ASSERT (commit_transaction->t_shadow_list == NULL); | |
705 | ||
706 | jbd_debug(3, "JBD: commit phase 5\n"); | |
707 | ||
708 | /* Here we wait for the revoke record and descriptor record buffers */ | |
709 | wait_for_ctlbuf: | |
710 | while (commit_transaction->t_log_list != NULL) { | |
711 | struct buffer_head *bh; | |
712 | ||
713 | jh = commit_transaction->t_log_list->b_tprev; | |
714 | bh = jh2bh(jh); | |
715 | if (buffer_locked(bh)) { | |
716 | wait_on_buffer(bh); | |
717 | goto wait_for_ctlbuf; | |
718 | } | |
719 | if (cond_resched()) | |
720 | goto wait_for_ctlbuf; | |
721 | ||
722 | if (unlikely(!buffer_uptodate(bh))) | |
723 | err = -EIO; | |
724 | ||
725 | BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); | |
726 | clear_buffer_jwrite(bh); | |
727 | journal_unfile_buffer(journal, jh); | |
728 | journal_put_journal_head(jh); | |
729 | __brelse(bh); /* One for getblk */ | |
730 | /* AKPM: bforget here */ | |
731 | } | |
732 | ||
733 | jbd_debug(3, "JBD: commit phase 6\n"); | |
734 | ||
735 | if (journal_write_commit_record(journal, commit_transaction)) | |
736 | err = -EIO; | |
737 | ||
738 | if (err) | |
7a266e75 | 739 | journal_abort(journal, err); |
1da177e4 LT |
740 | |
741 | /* End of a transaction! Finally, we can do checkpoint | |
742 | processing: any buffers committed as a result of this | |
743 | transaction can be removed from any checkpoint list it was on | |
744 | before. */ | |
745 | ||
746 | jbd_debug(3, "JBD: commit phase 7\n"); | |
747 | ||
748 | J_ASSERT(commit_transaction->t_sync_datalist == NULL); | |
749 | J_ASSERT(commit_transaction->t_buffers == NULL); | |
750 | J_ASSERT(commit_transaction->t_checkpoint_list == NULL); | |
751 | J_ASSERT(commit_transaction->t_iobuf_list == NULL); | |
752 | J_ASSERT(commit_transaction->t_shadow_list == NULL); | |
753 | J_ASSERT(commit_transaction->t_log_list == NULL); | |
754 | ||
755 | restart_loop: | |
e6c9f5c1 JK |
756 | /* |
757 | * As there are other places (journal_unmap_buffer()) adding buffers | |
758 | * to this list we have to be careful and hold the j_list_lock. | |
759 | */ | |
760 | spin_lock(&journal->j_list_lock); | |
1da177e4 LT |
761 | while (commit_transaction->t_forget) { |
762 | transaction_t *cp_transaction; | |
763 | struct buffer_head *bh; | |
764 | ||
765 | jh = commit_transaction->t_forget; | |
e6c9f5c1 | 766 | spin_unlock(&journal->j_list_lock); |
1da177e4 LT |
767 | bh = jh2bh(jh); |
768 | jbd_lock_bh_state(bh); | |
769 | J_ASSERT_JH(jh, jh->b_transaction == commit_transaction || | |
770 | jh->b_transaction == journal->j_running_transaction); | |
771 | ||
772 | /* | |
773 | * If there is undo-protected committed data against | |
774 | * this buffer, then we can remove it now. If it is a | |
775 | * buffer needing such protection, the old frozen_data | |
776 | * field now points to a committed version of the | |
777 | * buffer, so rotate that field to the new committed | |
778 | * data. | |
779 | * | |
780 | * Otherwise, we can just throw away the frozen data now. | |
781 | */ | |
782 | if (jh->b_committed_data) { | |
c089d490 | 783 | jbd_free(jh->b_committed_data, bh->b_size); |
1da177e4 LT |
784 | jh->b_committed_data = NULL; |
785 | if (jh->b_frozen_data) { | |
786 | jh->b_committed_data = jh->b_frozen_data; | |
787 | jh->b_frozen_data = NULL; | |
788 | } | |
789 | } else if (jh->b_frozen_data) { | |
c089d490 | 790 | jbd_free(jh->b_frozen_data, bh->b_size); |
1da177e4 LT |
791 | jh->b_frozen_data = NULL; |
792 | } | |
793 | ||
794 | spin_lock(&journal->j_list_lock); | |
795 | cp_transaction = jh->b_cp_transaction; | |
796 | if (cp_transaction) { | |
797 | JBUFFER_TRACE(jh, "remove from old cp transaction"); | |
798 | __journal_remove_checkpoint(jh); | |
799 | } | |
800 | ||
801 | /* Only re-checkpoint the buffer_head if it is marked | |
802 | * dirty. If the buffer was added to the BJ_Forget list | |
803 | * by journal_forget, it may no longer be dirty and | |
804 | * there's no point in keeping a checkpoint record for | |
805 | * it. */ | |
806 | ||
807 | /* A buffer which has been freed while still being | |
808 | * journaled by a previous transaction may end up still | |
809 | * being dirty here, but we want to avoid writing back | |
810 | * that buffer in the future now that the last use has | |
811 | * been committed. That's not only a performance gain, | |
812 | * it also stops aliasing problems if the buffer is left | |
813 | * behind for writeback and gets reallocated for another | |
814 | * use in a different page. */ | |
815 | if (buffer_freed(bh)) { | |
816 | clear_buffer_freed(bh); | |
817 | clear_buffer_jbddirty(bh); | |
818 | } | |
819 | ||
820 | if (buffer_jbddirty(bh)) { | |
821 | JBUFFER_TRACE(jh, "add to new checkpointing trans"); | |
822 | __journal_insert_checkpoint(jh, commit_transaction); | |
823 | JBUFFER_TRACE(jh, "refile for checkpoint writeback"); | |
824 | __journal_refile_buffer(jh); | |
825 | jbd_unlock_bh_state(bh); | |
826 | } else { | |
827 | J_ASSERT_BH(bh, !buffer_dirty(bh)); | |
9ada7340 JK |
828 | /* The buffer on BJ_Forget list and not jbddirty means |
829 | * it has been freed by this transaction and hence it | |
830 | * could not have been reallocated until this | |
831 | * transaction has committed. *BUT* it could be | |
832 | * reallocated once we have written all the data to | |
833 | * disk and before we process the buffer on BJ_Forget | |
834 | * list. */ | |
835 | JBUFFER_TRACE(jh, "refile or unfile freed buffer"); | |
836 | __journal_refile_buffer(jh); | |
837 | if (!jh->b_transaction) { | |
838 | jbd_unlock_bh_state(bh); | |
839 | /* needs a brelse */ | |
840 | journal_remove_journal_head(bh); | |
841 | release_buffer_page(bh); | |
842 | } else | |
843 | jbd_unlock_bh_state(bh); | |
1da177e4 | 844 | } |
e6c9f5c1 JK |
845 | cond_resched_lock(&journal->j_list_lock); |
846 | } | |
847 | spin_unlock(&journal->j_list_lock); | |
848 | /* | |
d4beaf4a JK |
849 | * This is a bit sleazy. We use j_list_lock to protect transition |
850 | * of a transaction into T_FINISHED state and calling | |
851 | * __journal_drop_transaction(). Otherwise we could race with | |
852 | * other checkpointing code processing the transaction... | |
e6c9f5c1 JK |
853 | */ |
854 | spin_lock(&journal->j_state_lock); | |
855 | spin_lock(&journal->j_list_lock); | |
856 | /* | |
857 | * Now recheck if some buffers did not get attached to the transaction | |
858 | * while the lock was dropped... | |
859 | */ | |
860 | if (commit_transaction->t_forget) { | |
1da177e4 | 861 | spin_unlock(&journal->j_list_lock); |
e6c9f5c1 JK |
862 | spin_unlock(&journal->j_state_lock); |
863 | goto restart_loop; | |
1da177e4 LT |
864 | } |
865 | ||
866 | /* Done with this transaction! */ | |
867 | ||
868 | jbd_debug(3, "JBD: commit phase 8\n"); | |
869 | ||
870 | J_ASSERT(commit_transaction->t_state == T_COMMIT); | |
871 | ||
1da177e4 LT |
872 | commit_transaction->t_state = T_FINISHED; |
873 | J_ASSERT(commit_transaction == journal->j_committing_transaction); | |
874 | journal->j_commit_sequence = commit_transaction->t_tid; | |
875 | journal->j_committing_transaction = NULL; | |
876 | spin_unlock(&journal->j_state_lock); | |
877 | ||
fe28e42b JK |
878 | if (commit_transaction->t_checkpoint_list == NULL && |
879 | commit_transaction->t_checkpoint_io_list == NULL) { | |
1da177e4 LT |
880 | __journal_drop_transaction(journal, commit_transaction); |
881 | } else { | |
882 | if (journal->j_checkpoint_transactions == NULL) { | |
883 | journal->j_checkpoint_transactions = commit_transaction; | |
884 | commit_transaction->t_cpnext = commit_transaction; | |
885 | commit_transaction->t_cpprev = commit_transaction; | |
886 | } else { | |
887 | commit_transaction->t_cpnext = | |
888 | journal->j_checkpoint_transactions; | |
889 | commit_transaction->t_cpprev = | |
890 | commit_transaction->t_cpnext->t_cpprev; | |
891 | commit_transaction->t_cpnext->t_cpprev = | |
892 | commit_transaction; | |
893 | commit_transaction->t_cpprev->t_cpnext = | |
894 | commit_transaction; | |
895 | } | |
896 | } | |
897 | spin_unlock(&journal->j_list_lock); | |
898 | ||
899 | jbd_debug(1, "JBD: commit %d complete, head %d\n", | |
900 | journal->j_commit_sequence, journal->j_tail_sequence); | |
901 | ||
902 | wake_up(&journal->j_wait_done_commit); | |
903 | } |