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1 | /* |
2 | * linux/fs/jbd/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/mm.h> |
21 | #include <linux/pagemap.h> |
22 | #include <linux/bio.h> |
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 successfully 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 journal->j_list_lock. The caller provided us with a ref |
49 | * 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 (!trylock_page(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 | * Decrement reference counter for data buffer. If it has been marked |
82 | * 'BH_Freed', release it and the page to which it belongs if possible. |
83 | */ |
84 | static void release_data_buffer(struct buffer_head *bh) |
85 | { |
86 | if (buffer_freed(bh)) { |
87 | clear_buffer_freed(bh); |
88 | release_buffer_page(bh); |
89 | } else |
90 | put_bh(bh); |
91 | } |
92 | |
93 | /* |
94 | * Try to acquire jbd_lock_bh_state() against the buffer, when j_list_lock is |
95 | * held. For ranking reasons we must trylock. If we lose, schedule away and |
96 | * return 0. j_list_lock is dropped in this case. |
97 | */ |
98 | static int inverted_lock(journal_t *journal, struct buffer_head *bh) |
99 | { |
100 | if (!jbd_trylock_bh_state(bh)) { |
101 | spin_unlock(&journal->j_list_lock); |
102 | schedule(); |
103 | return 0; |
104 | } |
105 | return 1; |
106 | } |
107 | |
108 | /* Done it all: now write the commit record. We should have |
109 | * cleaned up our previous buffers by now, so if we are in abort |
110 | * mode we can now just skip the rest of the journal write |
111 | * entirely. |
112 | * |
113 | * Returns 1 if the journal needs to be aborted or 0 on success |
114 | */ |
115 | static int journal_write_commit_record(journal_t *journal, |
116 | transaction_t *commit_transaction) |
117 | { |
118 | struct journal_head *descriptor; |
119 | struct buffer_head *bh; |
120 | journal_header_t *header; |
121 | int ret; |
122 | int barrier_done = 0; |
123 | |
124 | if (is_journal_aborted(journal)) |
125 | return 0; |
126 | |
127 | descriptor = journal_get_descriptor_buffer(journal); |
128 | if (!descriptor) |
129 | return 1; |
130 | |
131 | bh = jh2bh(descriptor); |
132 | |
133 | header = (journal_header_t *)(bh->b_data); |
134 | header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); |
135 | header->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK); |
136 | header->h_sequence = cpu_to_be32(commit_transaction->t_tid); |
137 | |
138 | JBUFFER_TRACE(descriptor, "write commit block"); |
139 | set_buffer_dirty(bh); |
140 | if (journal->j_flags & JFS_BARRIER) { |
141 | set_buffer_ordered(bh); |
142 | barrier_done = 1; |
143 | } |
144 | ret = sync_dirty_buffer(bh); |
145 | if (barrier_done) |
146 | clear_buffer_ordered(bh); |
147 | /* is it possible for another commit to fail at roughly |
148 | * the same time as this one? If so, we don't want to |
149 | * trust the barrier flag in the super, but instead want |
150 | * to remember if we sent a barrier request |
151 | */ |
152 | if (ret == -EOPNOTSUPP && barrier_done) { |
153 | char b[BDEVNAME_SIZE]; |
154 | |
155 | printk(KERN_WARNING |
156 | "JBD: barrier-based sync failed on %s - " |
157 | "disabling barriers\n", |
158 | bdevname(journal->j_dev, b)); |
159 | spin_lock(&journal->j_state_lock); |
160 | journal->j_flags &= ~JFS_BARRIER; |
161 | spin_unlock(&journal->j_state_lock); |
162 | |
163 | /* And try again, without the barrier */ |
164 | set_buffer_uptodate(bh); |
165 | set_buffer_dirty(bh); |
166 | ret = sync_dirty_buffer(bh); |
167 | } |
168 | put_bh(bh); /* One for getblk() */ |
169 | journal_put_journal_head(descriptor); |
170 | |
171 | return (ret == -EIO); |
172 | } |
173 | |
174 | static void journal_do_submit_data(struct buffer_head **wbuf, int bufs, |
175 | int write_op) |
176 | { |
177 | int i; |
178 | |
179 | for (i = 0; i < bufs; i++) { |
180 | wbuf[i]->b_end_io = end_buffer_write_sync; |
181 | /* We use-up our safety reference in submit_bh() */ |
182 | submit_bh(write_op, wbuf[i]); |
183 | } |
184 | } |
185 | |
186 | /* |
187 | * Submit all the data buffers to disk |
188 | */ |
189 | static int journal_submit_data_buffers(journal_t *journal, |
190 | transaction_t *commit_transaction, |
191 | int write_op) |
192 | { |
193 | struct journal_head *jh; |
194 | struct buffer_head *bh; |
195 | int locked; |
196 | int bufs = 0; |
197 | struct buffer_head **wbuf = journal->j_wbuf; |
198 | int err = 0; |
199 | |
200 | /* |
201 | * Whenever we unlock the journal and sleep, things can get added |
202 | * onto ->t_sync_datalist, so we have to keep looping back to |
203 | * write_out_data until we *know* that the list is empty. |
204 | * |
205 | * Cleanup any flushed data buffers from the data list. Even in |
206 | * abort mode, we want to flush this out as soon as possible. |
207 | */ |
208 | write_out_data: |
209 | cond_resched(); |
210 | spin_lock(&journal->j_list_lock); |
211 | |
212 | while (commit_transaction->t_sync_datalist) { |
213 | jh = commit_transaction->t_sync_datalist; |
214 | bh = jh2bh(jh); |
215 | locked = 0; |
216 | |
217 | /* Get reference just to make sure buffer does not disappear |
218 | * when we are forced to drop various locks */ |
219 | get_bh(bh); |
220 | /* If the buffer is dirty, we need to submit IO and hence |
221 | * we need the buffer lock. We try to lock the buffer without |
222 | * blocking. If we fail, we need to drop j_list_lock and do |
223 | * blocking lock_buffer(). |
224 | */ |
225 | if (buffer_dirty(bh)) { |
226 | if (!trylock_buffer(bh)) { |
227 | BUFFER_TRACE(bh, "needs blocking lock"); |
228 | spin_unlock(&journal->j_list_lock); |
229 | /* Write out all data to prevent deadlocks */ |
230 | journal_do_submit_data(wbuf, bufs, write_op); |
231 | bufs = 0; |
232 | lock_buffer(bh); |
233 | spin_lock(&journal->j_list_lock); |
234 | } |
235 | locked = 1; |
236 | } |
237 | /* We have to get bh_state lock. Again out of order, sigh. */ |
238 | if (!inverted_lock(journal, bh)) { |
239 | jbd_lock_bh_state(bh); |
240 | spin_lock(&journal->j_list_lock); |
241 | } |
242 | /* Someone already cleaned up the buffer? */ |
243 | if (!buffer_jbd(bh) || bh2jh(bh) != jh |
244 | || jh->b_transaction != commit_transaction |
245 | || jh->b_jlist != BJ_SyncData) { |
246 | jbd_unlock_bh_state(bh); |
247 | if (locked) |
248 | unlock_buffer(bh); |
249 | BUFFER_TRACE(bh, "already cleaned up"); |
250 | release_data_buffer(bh); |
251 | continue; |
252 | } |
253 | if (locked && test_clear_buffer_dirty(bh)) { |
254 | BUFFER_TRACE(bh, "needs writeout, adding to array"); |
255 | wbuf[bufs++] = bh; |
256 | __journal_file_buffer(jh, commit_transaction, |
257 | BJ_Locked); |
258 | jbd_unlock_bh_state(bh); |
259 | if (bufs == journal->j_wbufsize) { |
260 | spin_unlock(&journal->j_list_lock); |
261 | journal_do_submit_data(wbuf, bufs, write_op); |
262 | bufs = 0; |
263 | goto write_out_data; |
264 | } |
265 | } else if (!locked && buffer_locked(bh)) { |
266 | __journal_file_buffer(jh, commit_transaction, |
267 | BJ_Locked); |
268 | jbd_unlock_bh_state(bh); |
269 | put_bh(bh); |
270 | } else { |
271 | BUFFER_TRACE(bh, "writeout complete: unfile"); |
272 | if (unlikely(!buffer_uptodate(bh))) |
273 | err = -EIO; |
274 | __journal_unfile_buffer(jh); |
275 | jbd_unlock_bh_state(bh); |
276 | if (locked) |
277 | unlock_buffer(bh); |
278 | journal_remove_journal_head(bh); |
279 | /* One for our safety reference, other for |
280 | * journal_remove_journal_head() */ |
281 | put_bh(bh); |
282 | release_data_buffer(bh); |
283 | } |
284 | |
285 | if (need_resched() || spin_needbreak(&journal->j_list_lock)) { |
286 | spin_unlock(&journal->j_list_lock); |
287 | goto write_out_data; |
288 | } |
289 | } |
290 | spin_unlock(&journal->j_list_lock); |
291 | journal_do_submit_data(wbuf, bufs, write_op); |
292 | |
293 | return err; |
294 | } |
295 | |
296 | /* |
297 | * journal_commit_transaction |
298 | * |
299 | * The primary function for committing a transaction to the log. This |
300 | * function is called by the journal thread to begin a complete commit. |
301 | */ |
302 | void journal_commit_transaction(journal_t *journal) |
303 | { |
304 | transaction_t *commit_transaction; |
305 | struct journal_head *jh, *new_jh, *descriptor; |
306 | struct buffer_head **wbuf = journal->j_wbuf; |
307 | int bufs; |
308 | int flags; |
309 | int err; |
310 | unsigned int blocknr; |
311 | ktime_t start_time; |
312 | u64 commit_time; |
313 | char *tagp = NULL; |
314 | journal_header_t *header; |
315 | journal_block_tag_t *tag = NULL; |
316 | int space_left = 0; |
317 | int first_tag = 0; |
318 | int tag_flag; |
319 | int i; |
320 | int write_op = WRITE; |
321 | |
322 | /* |
323 | * First job: lock down the current transaction and wait for |
324 | * all outstanding updates to complete. |
325 | */ |
326 | |
327 | #ifdef COMMIT_STATS |
328 | spin_lock(&journal->j_list_lock); |
329 | summarise_journal_usage(journal); |
330 | spin_unlock(&journal->j_list_lock); |
331 | #endif |
332 | |
333 | /* Do we need to erase the effects of a prior journal_flush? */ |
334 | if (journal->j_flags & JFS_FLUSHED) { |
335 | jbd_debug(3, "super block updated\n"); |
336 | journal_update_superblock(journal, 1); |
337 | } else { |
338 | jbd_debug(3, "superblock not updated\n"); |
339 | } |
340 | |
341 | J_ASSERT(journal->j_running_transaction != NULL); |
342 | J_ASSERT(journal->j_committing_transaction == NULL); |
343 | |
344 | commit_transaction = journal->j_running_transaction; |
345 | J_ASSERT(commit_transaction->t_state == T_RUNNING); |
346 | |
347 | jbd_debug(1, "JBD: starting commit of transaction %d\n", |
348 | commit_transaction->t_tid); |
349 | |
350 | spin_lock(&journal->j_state_lock); |
351 | commit_transaction->t_state = T_LOCKED; |
352 | |
353 | /* |
354 | * Use plugged writes here, since we want to submit several before |
355 | * we unplug the device. We don't do explicit unplugging in here, |
356 | * instead we rely on sync_buffer() doing the unplug for us. |
357 | */ |
358 | if (commit_transaction->t_synchronous_commit) |
359 | write_op = WRITE_SYNC_PLUG; |
360 | spin_lock(&commit_transaction->t_handle_lock); |
361 | while (commit_transaction->t_updates) { |
362 | DEFINE_WAIT(wait); |
363 | |
364 | prepare_to_wait(&journal->j_wait_updates, &wait, |
365 | TASK_UNINTERRUPTIBLE); |
366 | if (commit_transaction->t_updates) { |
367 | spin_unlock(&commit_transaction->t_handle_lock); |
368 | spin_unlock(&journal->j_state_lock); |
369 | schedule(); |
370 | spin_lock(&journal->j_state_lock); |
371 | spin_lock(&commit_transaction->t_handle_lock); |
372 | } |
373 | finish_wait(&journal->j_wait_updates, &wait); |
374 | } |
375 | spin_unlock(&commit_transaction->t_handle_lock); |
376 | |
377 | J_ASSERT (commit_transaction->t_outstanding_credits <= |
378 | journal->j_max_transaction_buffers); |
379 | |
380 | /* |
381 | * First thing we are allowed to do is to discard any remaining |
382 | * BJ_Reserved buffers. Note, it is _not_ permissible to assume |
383 | * that there are no such buffers: if a large filesystem |
384 | * operation like a truncate needs to split itself over multiple |
385 | * transactions, then it may try to do a journal_restart() while |
386 | * there are still BJ_Reserved buffers outstanding. These must |
387 | * be released cleanly from the current transaction. |
388 | * |
389 | * In this case, the filesystem must still reserve write access |
390 | * again before modifying the buffer in the new transaction, but |
391 | * we do not require it to remember exactly which old buffers it |
392 | * has reserved. This is consistent with the existing behaviour |
393 | * that multiple journal_get_write_access() calls to the same |
394 | * buffer are perfectly permissable. |
395 | */ |
396 | while (commit_transaction->t_reserved_list) { |
397 | jh = commit_transaction->t_reserved_list; |
398 | JBUFFER_TRACE(jh, "reserved, unused: refile"); |
399 | /* |
400 | * A journal_get_undo_access()+journal_release_buffer() may |
401 | * leave undo-committed data. |
402 | */ |
403 | if (jh->b_committed_data) { |
404 | struct buffer_head *bh = jh2bh(jh); |
405 | |
406 | jbd_lock_bh_state(bh); |
407 | jbd_free(jh->b_committed_data, bh->b_size); |
408 | jh->b_committed_data = NULL; |
409 | jbd_unlock_bh_state(bh); |
410 | } |
411 | journal_refile_buffer(journal, jh); |
412 | } |
413 | |
414 | /* |
415 | * Now try to drop any written-back buffers from the journal's |
416 | * checkpoint lists. We do this *before* commit because it potentially |
417 | * frees some memory |
418 | */ |
419 | spin_lock(&journal->j_list_lock); |
420 | __journal_clean_checkpoint_list(journal); |
421 | spin_unlock(&journal->j_list_lock); |
422 | |
423 | jbd_debug (3, "JBD: commit phase 1\n"); |
424 | |
425 | /* |
426 | * Switch to a new revoke table. |
427 | */ |
428 | journal_switch_revoke_table(journal); |
429 | |
430 | commit_transaction->t_state = T_FLUSH; |
431 | journal->j_committing_transaction = commit_transaction; |
432 | journal->j_running_transaction = NULL; |
433 | start_time = ktime_get(); |
434 | commit_transaction->t_log_start = journal->j_head; |
435 | wake_up(&journal->j_wait_transaction_locked); |
436 | spin_unlock(&journal->j_state_lock); |
437 | |
438 | jbd_debug (3, "JBD: commit phase 2\n"); |
439 | |
440 | /* |
441 | * Now start flushing things to disk, in the order they appear |
442 | * on the transaction lists. Data blocks go first. |
443 | */ |
444 | err = journal_submit_data_buffers(journal, commit_transaction, |
445 | write_op); |
446 | |
447 | /* |
448 | * Wait for all previously submitted IO to complete. |
449 | */ |
450 | spin_lock(&journal->j_list_lock); |
451 | while (commit_transaction->t_locked_list) { |
452 | struct buffer_head *bh; |
453 | |
454 | jh = commit_transaction->t_locked_list->b_tprev; |
455 | bh = jh2bh(jh); |
456 | get_bh(bh); |
457 | if (buffer_locked(bh)) { |
458 | spin_unlock(&journal->j_list_lock); |
459 | wait_on_buffer(bh); |
460 | spin_lock(&journal->j_list_lock); |
461 | } |
462 | if (unlikely(!buffer_uptodate(bh))) { |
463 | if (!trylock_page(bh->b_page)) { |
464 | spin_unlock(&journal->j_list_lock); |
465 | lock_page(bh->b_page); |
466 | spin_lock(&journal->j_list_lock); |
467 | } |
468 | if (bh->b_page->mapping) |
469 | set_bit(AS_EIO, &bh->b_page->mapping->flags); |
470 | |
471 | unlock_page(bh->b_page); |
472 | SetPageError(bh->b_page); |
473 | err = -EIO; |
474 | } |
475 | if (!inverted_lock(journal, bh)) { |
476 | put_bh(bh); |
477 | spin_lock(&journal->j_list_lock); |
478 | continue; |
479 | } |
480 | if (buffer_jbd(bh) && bh2jh(bh) == jh && |
481 | jh->b_transaction == commit_transaction && |
482 | jh->b_jlist == BJ_Locked) { |
483 | __journal_unfile_buffer(jh); |
484 | jbd_unlock_bh_state(bh); |
485 | journal_remove_journal_head(bh); |
486 | put_bh(bh); |
487 | } else { |
488 | jbd_unlock_bh_state(bh); |
489 | } |
490 | release_data_buffer(bh); |
491 | cond_resched_lock(&journal->j_list_lock); |
492 | } |
493 | spin_unlock(&journal->j_list_lock); |
494 | |
495 | if (err) { |
496 | char b[BDEVNAME_SIZE]; |
497 | |
498 | printk(KERN_WARNING |
499 | "JBD: Detected IO errors while flushing file data " |
500 | "on %s\n", bdevname(journal->j_fs_dev, b)); |
501 | if (journal->j_flags & JFS_ABORT_ON_SYNCDATA_ERR) |
502 | journal_abort(journal, err); |
503 | err = 0; |
504 | } |
505 | |
506 | journal_write_revoke_records(journal, commit_transaction, write_op); |
507 | |
508 | /* |
509 | * If we found any dirty or locked buffers, then we should have |
510 | * looped back up to the write_out_data label. If there weren't |
511 | * any then journal_clean_data_list should have wiped the list |
512 | * clean by now, so check that it is in fact empty. |
513 | */ |
514 | J_ASSERT (commit_transaction->t_sync_datalist == NULL); |
515 | |
516 | jbd_debug (3, "JBD: commit phase 3\n"); |
517 | |
518 | /* |
519 | * Way to go: we have now written out all of the data for a |
520 | * transaction! Now comes the tricky part: we need to write out |
521 | * metadata. Loop over the transaction's entire buffer list: |
522 | */ |
523 | spin_lock(&journal->j_state_lock); |
524 | commit_transaction->t_state = T_COMMIT; |
525 | spin_unlock(&journal->j_state_lock); |
526 | |
527 | J_ASSERT(commit_transaction->t_nr_buffers <= |
528 | commit_transaction->t_outstanding_credits); |
529 | |
530 | descriptor = NULL; |
531 | bufs = 0; |
532 | while (commit_transaction->t_buffers) { |
533 | |
534 | /* Find the next buffer to be journaled... */ |
535 | |
536 | jh = commit_transaction->t_buffers; |
537 | |
538 | /* If we're in abort mode, we just un-journal the buffer and |
539 | release it. */ |
540 | |
541 | if (is_journal_aborted(journal)) { |
542 | clear_buffer_jbddirty(jh2bh(jh)); |
543 | JBUFFER_TRACE(jh, "journal is aborting: refile"); |
544 | journal_refile_buffer(journal, jh); |
545 | /* If that was the last one, we need to clean up |
546 | * any descriptor buffers which may have been |
547 | * already allocated, even if we are now |
548 | * aborting. */ |
549 | if (!commit_transaction->t_buffers) |
550 | goto start_journal_io; |
551 | continue; |
552 | } |
553 | |
554 | /* Make sure we have a descriptor block in which to |
555 | record the metadata buffer. */ |
556 | |
557 | if (!descriptor) { |
558 | struct buffer_head *bh; |
559 | |
560 | J_ASSERT (bufs == 0); |
561 | |
562 | jbd_debug(4, "JBD: get descriptor\n"); |
563 | |
564 | descriptor = journal_get_descriptor_buffer(journal); |
565 | if (!descriptor) { |
566 | journal_abort(journal, -EIO); |
567 | continue; |
568 | } |
569 | |
570 | bh = jh2bh(descriptor); |
571 | jbd_debug(4, "JBD: got buffer %llu (%p)\n", |
572 | (unsigned long long)bh->b_blocknr, bh->b_data); |
573 | header = (journal_header_t *)&bh->b_data[0]; |
574 | header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); |
575 | header->h_blocktype = cpu_to_be32(JFS_DESCRIPTOR_BLOCK); |
576 | header->h_sequence = cpu_to_be32(commit_transaction->t_tid); |
577 | |
578 | tagp = &bh->b_data[sizeof(journal_header_t)]; |
579 | space_left = bh->b_size - sizeof(journal_header_t); |
580 | first_tag = 1; |
581 | set_buffer_jwrite(bh); |
582 | set_buffer_dirty(bh); |
583 | wbuf[bufs++] = bh; |
584 | |
585 | /* Record it so that we can wait for IO |
586 | completion later */ |
587 | BUFFER_TRACE(bh, "ph3: file as descriptor"); |
588 | journal_file_buffer(descriptor, commit_transaction, |
589 | BJ_LogCtl); |
590 | } |
591 | |
592 | /* Where is the buffer to be written? */ |
593 | |
594 | err = journal_next_log_block(journal, &blocknr); |
595 | /* If the block mapping failed, just abandon the buffer |
596 | and repeat this loop: we'll fall into the |
597 | refile-on-abort condition above. */ |
598 | if (err) { |
599 | journal_abort(journal, err); |
600 | continue; |
601 | } |
602 | |
603 | /* |
604 | * start_this_handle() uses t_outstanding_credits to determine |
605 | * the free space in the log, but this counter is changed |
606 | * by journal_next_log_block() also. |
607 | */ |
608 | commit_transaction->t_outstanding_credits--; |
609 | |
610 | /* Bump b_count to prevent truncate from stumbling over |
611 | the shadowed buffer! @@@ This can go if we ever get |
612 | rid of the BJ_IO/BJ_Shadow pairing of buffers. */ |
613 | atomic_inc(&jh2bh(jh)->b_count); |
614 | |
615 | /* Make a temporary IO buffer with which to write it out |
616 | (this will requeue both the metadata buffer and the |
617 | temporary IO buffer). new_bh goes on BJ_IO*/ |
618 | |
619 | set_bit(BH_JWrite, &jh2bh(jh)->b_state); |
620 | /* |
621 | * akpm: journal_write_metadata_buffer() sets |
622 | * new_bh->b_transaction to commit_transaction. |
623 | * We need to clean this up before we release new_bh |
624 | * (which is of type BJ_IO) |
625 | */ |
626 | JBUFFER_TRACE(jh, "ph3: write metadata"); |
627 | flags = journal_write_metadata_buffer(commit_transaction, |
628 | jh, &new_jh, blocknr); |
629 | set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); |
630 | wbuf[bufs++] = jh2bh(new_jh); |
631 | |
632 | /* Record the new block's tag in the current descriptor |
633 | buffer */ |
634 | |
635 | tag_flag = 0; |
636 | if (flags & 1) |
637 | tag_flag |= JFS_FLAG_ESCAPE; |
638 | if (!first_tag) |
639 | tag_flag |= JFS_FLAG_SAME_UUID; |
640 | |
641 | tag = (journal_block_tag_t *) tagp; |
642 | tag->t_blocknr = cpu_to_be32(jh2bh(jh)->b_blocknr); |
643 | tag->t_flags = cpu_to_be32(tag_flag); |
644 | tagp += sizeof(journal_block_tag_t); |
645 | space_left -= sizeof(journal_block_tag_t); |
646 | |
647 | if (first_tag) { |
648 | memcpy (tagp, journal->j_uuid, 16); |
649 | tagp += 16; |
650 | space_left -= 16; |
651 | first_tag = 0; |
652 | } |
653 | |
654 | /* If there's no more to do, or if the descriptor is full, |
655 | let the IO rip! */ |
656 | |
657 | if (bufs == journal->j_wbufsize || |
658 | commit_transaction->t_buffers == NULL || |
659 | space_left < sizeof(journal_block_tag_t) + 16) { |
660 | |
661 | jbd_debug(4, "JBD: Submit %d IOs\n", bufs); |
662 | |
663 | /* Write an end-of-descriptor marker before |
664 | submitting the IOs. "tag" still points to |
665 | the last tag we set up. */ |
666 | |
667 | tag->t_flags |= cpu_to_be32(JFS_FLAG_LAST_TAG); |
668 | |
669 | start_journal_io: |
670 | for (i = 0; i < bufs; i++) { |
671 | struct buffer_head *bh = wbuf[i]; |
672 | lock_buffer(bh); |
673 | clear_buffer_dirty(bh); |
674 | set_buffer_uptodate(bh); |
675 | bh->b_end_io = journal_end_buffer_io_sync; |
676 | submit_bh(write_op, bh); |
677 | } |
678 | cond_resched(); |
679 | |
680 | /* Force a new descriptor to be generated next |
681 | time round the loop. */ |
682 | descriptor = NULL; |
683 | bufs = 0; |
684 | } |
685 | } |
686 | |
687 | /* Lo and behold: we have just managed to send a transaction to |
688 | the log. Before we can commit it, wait for the IO so far to |
689 | complete. Control buffers being written are on the |
690 | transaction's t_log_list queue, and metadata buffers are on |
691 | the t_iobuf_list queue. |
692 | |
693 | Wait for the buffers in reverse order. That way we are |
694 | less likely to be woken up until all IOs have completed, and |
695 | so we incur less scheduling load. |
696 | */ |
697 | |
698 | jbd_debug(3, "JBD: commit phase 4\n"); |
699 | |
700 | /* |
701 | * akpm: these are BJ_IO, and j_list_lock is not needed. |
702 | * See __journal_try_to_free_buffer. |
703 | */ |
704 | wait_for_iobuf: |
705 | while (commit_transaction->t_iobuf_list != NULL) { |
706 | struct buffer_head *bh; |
707 | |
708 | jh = commit_transaction->t_iobuf_list->b_tprev; |
709 | bh = jh2bh(jh); |
710 | if (buffer_locked(bh)) { |
711 | wait_on_buffer(bh); |
712 | goto wait_for_iobuf; |
713 | } |
714 | if (cond_resched()) |
715 | goto wait_for_iobuf; |
716 | |
717 | if (unlikely(!buffer_uptodate(bh))) |
718 | err = -EIO; |
719 | |
720 | clear_buffer_jwrite(bh); |
721 | |
722 | JBUFFER_TRACE(jh, "ph4: unfile after journal write"); |
723 | journal_unfile_buffer(journal, jh); |
724 | |
725 | /* |
726 | * ->t_iobuf_list should contain only dummy buffer_heads |
727 | * which were created by journal_write_metadata_buffer(). |
728 | */ |
729 | BUFFER_TRACE(bh, "dumping temporary bh"); |
730 | journal_put_journal_head(jh); |
731 | __brelse(bh); |
732 | J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); |
733 | free_buffer_head(bh); |
734 | |
735 | /* We also have to unlock and free the corresponding |
736 | shadowed buffer */ |
737 | jh = commit_transaction->t_shadow_list->b_tprev; |
738 | bh = jh2bh(jh); |
739 | clear_bit(BH_JWrite, &bh->b_state); |
740 | J_ASSERT_BH(bh, buffer_jbddirty(bh)); |
741 | |
742 | /* The metadata is now released for reuse, but we need |
743 | to remember it against this transaction so that when |
744 | we finally commit, we can do any checkpointing |
745 | required. */ |
746 | JBUFFER_TRACE(jh, "file as BJ_Forget"); |
747 | journal_file_buffer(jh, commit_transaction, BJ_Forget); |
748 | /* Wake up any transactions which were waiting for this |
749 | IO to complete */ |
750 | wake_up_bit(&bh->b_state, BH_Unshadow); |
751 | JBUFFER_TRACE(jh, "brelse shadowed buffer"); |
752 | __brelse(bh); |
753 | } |
754 | |
755 | J_ASSERT (commit_transaction->t_shadow_list == NULL); |
756 | |
757 | jbd_debug(3, "JBD: commit phase 5\n"); |
758 | |
759 | /* Here we wait for the revoke record and descriptor record buffers */ |
760 | wait_for_ctlbuf: |
761 | while (commit_transaction->t_log_list != NULL) { |
762 | struct buffer_head *bh; |
763 | |
764 | jh = commit_transaction->t_log_list->b_tprev; |
765 | bh = jh2bh(jh); |
766 | if (buffer_locked(bh)) { |
767 | wait_on_buffer(bh); |
768 | goto wait_for_ctlbuf; |
769 | } |
770 | if (cond_resched()) |
771 | goto wait_for_ctlbuf; |
772 | |
773 | if (unlikely(!buffer_uptodate(bh))) |
774 | err = -EIO; |
775 | |
776 | BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); |
777 | clear_buffer_jwrite(bh); |
778 | journal_unfile_buffer(journal, jh); |
779 | journal_put_journal_head(jh); |
780 | __brelse(bh); /* One for getblk */ |
781 | /* AKPM: bforget here */ |
782 | } |
783 | |
784 | if (err) |
785 | journal_abort(journal, err); |
786 | |
787 | jbd_debug(3, "JBD: commit phase 6\n"); |
788 | |
789 | if (journal_write_commit_record(journal, commit_transaction)) |
790 | err = -EIO; |
791 | |
792 | if (err) |
793 | journal_abort(journal, err); |
794 | |
795 | /* End of a transaction! Finally, we can do checkpoint |
796 | processing: any buffers committed as a result of this |
797 | transaction can be removed from any checkpoint list it was on |
798 | before. */ |
799 | |
800 | jbd_debug(3, "JBD: commit phase 7\n"); |
801 | |
802 | J_ASSERT(commit_transaction->t_sync_datalist == NULL); |
803 | J_ASSERT(commit_transaction->t_buffers == NULL); |
804 | J_ASSERT(commit_transaction->t_checkpoint_list == NULL); |
805 | J_ASSERT(commit_transaction->t_iobuf_list == NULL); |
806 | J_ASSERT(commit_transaction->t_shadow_list == NULL); |
807 | J_ASSERT(commit_transaction->t_log_list == NULL); |
808 | |
809 | restart_loop: |
810 | /* |
811 | * As there are other places (journal_unmap_buffer()) adding buffers |
812 | * to this list we have to be careful and hold the j_list_lock. |
813 | */ |
814 | spin_lock(&journal->j_list_lock); |
815 | while (commit_transaction->t_forget) { |
816 | transaction_t *cp_transaction; |
817 | struct buffer_head *bh; |
818 | |
819 | jh = commit_transaction->t_forget; |
820 | spin_unlock(&journal->j_list_lock); |
821 | bh = jh2bh(jh); |
822 | jbd_lock_bh_state(bh); |
823 | J_ASSERT_JH(jh, jh->b_transaction == commit_transaction || |
824 | jh->b_transaction == journal->j_running_transaction); |
825 | |
826 | /* |
827 | * If there is undo-protected committed data against |
828 | * this buffer, then we can remove it now. If it is a |
829 | * buffer needing such protection, the old frozen_data |
830 | * field now points to a committed version of the |
831 | * buffer, so rotate that field to the new committed |
832 | * data. |
833 | * |
834 | * Otherwise, we can just throw away the frozen data now. |
835 | */ |
836 | if (jh->b_committed_data) { |
837 | jbd_free(jh->b_committed_data, bh->b_size); |
838 | jh->b_committed_data = NULL; |
839 | if (jh->b_frozen_data) { |
840 | jh->b_committed_data = jh->b_frozen_data; |
841 | jh->b_frozen_data = NULL; |
842 | } |
843 | } else if (jh->b_frozen_data) { |
844 | jbd_free(jh->b_frozen_data, bh->b_size); |
845 | jh->b_frozen_data = NULL; |
846 | } |
847 | |
848 | spin_lock(&journal->j_list_lock); |
849 | cp_transaction = jh->b_cp_transaction; |
850 | if (cp_transaction) { |
851 | JBUFFER_TRACE(jh, "remove from old cp transaction"); |
852 | __journal_remove_checkpoint(jh); |
853 | } |
854 | |
855 | /* Only re-checkpoint the buffer_head if it is marked |
856 | * dirty. If the buffer was added to the BJ_Forget list |
857 | * by journal_forget, it may no longer be dirty and |
858 | * there's no point in keeping a checkpoint record for |
859 | * it. */ |
860 | |
861 | /* A buffer which has been freed while still being |
862 | * journaled by a previous transaction may end up still |
863 | * being dirty here, but we want to avoid writing back |
864 | * that buffer in the future after the "add to orphan" |
865 | * operation been committed, That's not only a performance |
866 | * gain, it also stops aliasing problems if the buffer is |
867 | * left behind for writeback and gets reallocated for another |
868 | * use in a different page. */ |
869 | if (buffer_freed(bh) && !jh->b_next_transaction) { |
870 | clear_buffer_freed(bh); |
871 | clear_buffer_jbddirty(bh); |
872 | } |
873 | |
874 | if (buffer_jbddirty(bh)) { |
875 | JBUFFER_TRACE(jh, "add to new checkpointing trans"); |
876 | __journal_insert_checkpoint(jh, commit_transaction); |
877 | if (is_journal_aborted(journal)) |
878 | clear_buffer_jbddirty(bh); |
879 | JBUFFER_TRACE(jh, "refile for checkpoint writeback"); |
880 | __journal_refile_buffer(jh); |
881 | jbd_unlock_bh_state(bh); |
882 | } else { |
883 | J_ASSERT_BH(bh, !buffer_dirty(bh)); |
884 | /* The buffer on BJ_Forget list and not jbddirty means |
885 | * it has been freed by this transaction and hence it |
886 | * could not have been reallocated until this |
887 | * transaction has committed. *BUT* it could be |
888 | * reallocated once we have written all the data to |
889 | * disk and before we process the buffer on BJ_Forget |
890 | * list. */ |
891 | JBUFFER_TRACE(jh, "refile or unfile freed buffer"); |
892 | __journal_refile_buffer(jh); |
893 | if (!jh->b_transaction) { |
894 | jbd_unlock_bh_state(bh); |
895 | /* needs a brelse */ |
896 | journal_remove_journal_head(bh); |
897 | release_buffer_page(bh); |
898 | } else |
899 | jbd_unlock_bh_state(bh); |
900 | } |
901 | cond_resched_lock(&journal->j_list_lock); |
902 | } |
903 | spin_unlock(&journal->j_list_lock); |
904 | /* |
905 | * This is a bit sleazy. We use j_list_lock to protect transition |
906 | * of a transaction into T_FINISHED state and calling |
907 | * __journal_drop_transaction(). Otherwise we could race with |
908 | * other checkpointing code processing the transaction... |
909 | */ |
910 | spin_lock(&journal->j_state_lock); |
911 | spin_lock(&journal->j_list_lock); |
912 | /* |
913 | * Now recheck if some buffers did not get attached to the transaction |
914 | * while the lock was dropped... |
915 | */ |
916 | if (commit_transaction->t_forget) { |
917 | spin_unlock(&journal->j_list_lock); |
918 | spin_unlock(&journal->j_state_lock); |
919 | goto restart_loop; |
920 | } |
921 | |
922 | /* Done with this transaction! */ |
923 | |
924 | jbd_debug(3, "JBD: commit phase 8\n"); |
925 | |
926 | J_ASSERT(commit_transaction->t_state == T_COMMIT); |
927 | |
928 | commit_transaction->t_state = T_FINISHED; |
929 | J_ASSERT(commit_transaction == journal->j_committing_transaction); |
930 | journal->j_commit_sequence = commit_transaction->t_tid; |
931 | journal->j_committing_transaction = NULL; |
932 | commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); |
933 | |
934 | /* |
935 | * weight the commit time higher than the average time so we don't |
936 | * react too strongly to vast changes in commit time |
937 | */ |
938 | if (likely(journal->j_average_commit_time)) |
939 | journal->j_average_commit_time = (commit_time*3 + |
940 | journal->j_average_commit_time) / 4; |
941 | else |
942 | journal->j_average_commit_time = commit_time; |
943 | |
944 | spin_unlock(&journal->j_state_lock); |
945 | |
946 | if (commit_transaction->t_checkpoint_list == NULL && |
947 | commit_transaction->t_checkpoint_io_list == NULL) { |
948 | __journal_drop_transaction(journal, commit_transaction); |
949 | } else { |
950 | if (journal->j_checkpoint_transactions == NULL) { |
951 | journal->j_checkpoint_transactions = commit_transaction; |
952 | commit_transaction->t_cpnext = commit_transaction; |
953 | commit_transaction->t_cpprev = commit_transaction; |
954 | } else { |
955 | commit_transaction->t_cpnext = |
956 | journal->j_checkpoint_transactions; |
957 | commit_transaction->t_cpprev = |
958 | commit_transaction->t_cpnext->t_cpprev; |
959 | commit_transaction->t_cpnext->t_cpprev = |
960 | commit_transaction; |
961 | commit_transaction->t_cpprev->t_cpnext = |
962 | commit_transaction; |
963 | } |
964 | } |
965 | spin_unlock(&journal->j_list_lock); |
966 | |
967 | jbd_debug(1, "JBD: commit %d complete, head %d\n", |
968 | journal->j_commit_sequence, journal->j_tail_sequence); |
969 | |
970 | wake_up(&journal->j_wait_done_commit); |
971 | } |
972 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
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