blob: 737f7246a4b5ddc750b4a5198928f4b5afacc193 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Uwe Zeisbergerf30c2262006-10-03 23:01:26 +02002 * linux/fs/jbd/journal.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
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 * Generic filesystem journal-writing code; part of the ext2fs
13 * journaling system.
14 *
15 * This file manages journals: areas of disk reserved for logging
16 * transactional updates. This includes the kernel journaling thread
17 * which is responsible for scheduling updates to the log.
18 *
19 * We do not actually manage the physical storage of the journal in this
20 * file: that is left to a per-journal policy function, which allows us
21 * to store the journal within a filesystem-specified area for ext2
22 * journaling (ext2 can use a reserved inode for storing the log).
23 */
24
25#include <linux/module.h>
26#include <linux/time.h>
27#include <linux/fs.h>
28#include <linux/jbd.h>
29#include <linux/errno.h>
30#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <linux/init.h>
32#include <linux/mm.h>
Nigel Cunningham7dfb7102006-12-06 20:34:23 -080033#include <linux/freezer.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <linux/pagemap.h>
Andrew Morton8d8c8512006-03-25 03:06:53 -080035#include <linux/kthread.h>
Randy Dunlapc9cf5522006-06-27 02:53:52 -070036#include <linux/poison.h>
Andrew Morton8d8c8512006-03-25 03:06:53 -080037#include <linux/proc_fs.h>
Jose R. Santosc2a91592007-10-18 23:39:22 -070038#include <linux/debugfs.h>
Andrew Morton8d8c8512006-03-25 03:06:53 -080039
Linus Torvalds1da177e2005-04-16 15:20:36 -070040#include <asm/uaccess.h>
41#include <asm/page.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
43EXPORT_SYMBOL(journal_start);
44EXPORT_SYMBOL(journal_restart);
45EXPORT_SYMBOL(journal_extend);
46EXPORT_SYMBOL(journal_stop);
47EXPORT_SYMBOL(journal_lock_updates);
48EXPORT_SYMBOL(journal_unlock_updates);
49EXPORT_SYMBOL(journal_get_write_access);
50EXPORT_SYMBOL(journal_get_create_access);
51EXPORT_SYMBOL(journal_get_undo_access);
52EXPORT_SYMBOL(journal_dirty_data);
53EXPORT_SYMBOL(journal_dirty_metadata);
54EXPORT_SYMBOL(journal_release_buffer);
55EXPORT_SYMBOL(journal_forget);
56#if 0
57EXPORT_SYMBOL(journal_sync_buffer);
58#endif
59EXPORT_SYMBOL(journal_flush);
60EXPORT_SYMBOL(journal_revoke);
61
62EXPORT_SYMBOL(journal_init_dev);
63EXPORT_SYMBOL(journal_init_inode);
64EXPORT_SYMBOL(journal_update_format);
65EXPORT_SYMBOL(journal_check_used_features);
66EXPORT_SYMBOL(journal_check_available_features);
67EXPORT_SYMBOL(journal_set_features);
68EXPORT_SYMBOL(journal_create);
69EXPORT_SYMBOL(journal_load);
70EXPORT_SYMBOL(journal_destroy);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071EXPORT_SYMBOL(journal_abort);
72EXPORT_SYMBOL(journal_errno);
73EXPORT_SYMBOL(journal_ack_err);
74EXPORT_SYMBOL(journal_clear_err);
75EXPORT_SYMBOL(log_wait_commit);
76EXPORT_SYMBOL(journal_start_commit);
77EXPORT_SYMBOL(journal_force_commit_nested);
78EXPORT_SYMBOL(journal_wipe);
79EXPORT_SYMBOL(journal_blocks_per_page);
80EXPORT_SYMBOL(journal_invalidatepage);
81EXPORT_SYMBOL(journal_try_to_free_buffers);
82EXPORT_SYMBOL(journal_force_commit);
83
84static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
Adrian Bunk022a4a72005-09-06 15:16:41 -070085static void __journal_abort_soft (journal_t *journal, int errno);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
87/*
88 * Helper function used to manage commit timeouts
89 */
90
91static void commit_timeout(unsigned long __data)
92{
93 struct task_struct * p = (struct task_struct *) __data;
94
95 wake_up_process(p);
96}
97
Linus Torvalds1da177e2005-04-16 15:20:36 -070098/*
99 * kjournald: The main thread function used to manage a logging device
100 * journal.
101 *
102 * This kernel thread is responsible for two things:
103 *
104 * 1) COMMIT: Every so often we need to commit the current state of the
105 * filesystem to disk. The journal thread is responsible for writing
106 * all of the metadata buffers to disk.
107 *
108 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
109 * of the data in that part of the log has been rewritten elsewhere on
110 * the disk. Flushing these old buffers to reclaim space in the log is
111 * known as checkpointing, and this thread is responsible for that job.
112 */
113
Adrian Bunk022a4a72005-09-06 15:16:41 -0700114static int kjournald(void *arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115{
Andrew Mortone3df1892006-03-25 03:06:53 -0800116 journal_t *journal = arg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 transaction_t *transaction;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118
Andrew Mortone3df1892006-03-25 03:06:53 -0800119 /*
120 * Set up an interval timer which can be used to trigger a commit wakeup
121 * after the commit interval expires
122 */
123 setup_timer(&journal->j_commit_timer, commit_timeout,
124 (unsigned long)current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125
126 /* Record that the journal thread is running */
127 journal->j_task = current;
128 wake_up(&journal->j_wait_done_commit);
129
130 printk(KERN_INFO "kjournald starting. Commit interval %ld seconds\n",
131 journal->j_commit_interval / HZ);
132
133 /*
134 * And now, wait forever for commit wakeup events.
135 */
136 spin_lock(&journal->j_state_lock);
137
138loop:
139 if (journal->j_flags & JFS_UNMOUNT)
140 goto end_loop;
141
142 jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
143 journal->j_commit_sequence, journal->j_commit_request);
144
145 if (journal->j_commit_sequence != journal->j_commit_request) {
146 jbd_debug(1, "OK, requests differ\n");
147 spin_unlock(&journal->j_state_lock);
Andrew Mortone3df1892006-03-25 03:06:53 -0800148 del_timer_sync(&journal->j_commit_timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 journal_commit_transaction(journal);
150 spin_lock(&journal->j_state_lock);
151 goto loop;
152 }
153
154 wake_up(&journal->j_wait_done_commit);
Christoph Lameter3e1d1d22005-06-24 23:13:50 -0700155 if (freezing(current)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 /*
157 * The simpler the better. Flushing journal isn't a
158 * good idea, because that depends on threads that may
159 * be already stopped.
160 */
161 jbd_debug(1, "Now suspending kjournald\n");
162 spin_unlock(&journal->j_state_lock);
Christoph Lameter3e1d1d22005-06-24 23:13:50 -0700163 refrigerator();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 spin_lock(&journal->j_state_lock);
165 } else {
166 /*
167 * We assume on resume that commits are already there,
168 * so we don't sleep
169 */
170 DEFINE_WAIT(wait);
171 int should_sleep = 1;
172
173 prepare_to_wait(&journal->j_wait_commit, &wait,
174 TASK_INTERRUPTIBLE);
175 if (journal->j_commit_sequence != journal->j_commit_request)
176 should_sleep = 0;
177 transaction = journal->j_running_transaction;
178 if (transaction && time_after_eq(jiffies,
179 transaction->t_expires))
180 should_sleep = 0;
Mark Fashehcbf0d272005-09-06 15:19:08 -0700181 if (journal->j_flags & JFS_UNMOUNT)
Dave Kleikampe9ad5622006-09-27 01:49:35 -0700182 should_sleep = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 if (should_sleep) {
184 spin_unlock(&journal->j_state_lock);
185 schedule();
186 spin_lock(&journal->j_state_lock);
187 }
188 finish_wait(&journal->j_wait_commit, &wait);
189 }
190
191 jbd_debug(1, "kjournald wakes\n");
192
193 /*
194 * Were we woken up by a commit wakeup event?
195 */
196 transaction = journal->j_running_transaction;
197 if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
198 journal->j_commit_request = transaction->t_tid;
199 jbd_debug(1, "woke because of timeout\n");
200 }
201 goto loop;
202
203end_loop:
204 spin_unlock(&journal->j_state_lock);
Andrew Mortone3df1892006-03-25 03:06:53 -0800205 del_timer_sync(&journal->j_commit_timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 journal->j_task = NULL;
207 wake_up(&journal->j_wait_done_commit);
208 jbd_debug(1, "Journal thread exiting.\n");
209 return 0;
210}
211
Pavel Emelianov97f06782007-05-08 00:30:42 -0700212static int journal_start_thread(journal_t *journal)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213{
Pavel Emelianov97f06782007-05-08 00:30:42 -0700214 struct task_struct *t;
215
216 t = kthread_run(kjournald, journal, "kjournald");
217 if (IS_ERR(t))
218 return PTR_ERR(t);
219
Stephen Hemmingerc80544d2007-10-18 03:07:05 -0700220 wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
Pavel Emelianov97f06782007-05-08 00:30:42 -0700221 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222}
223
224static void journal_kill_thread(journal_t *journal)
225{
226 spin_lock(&journal->j_state_lock);
227 journal->j_flags |= JFS_UNMOUNT;
228
229 while (journal->j_task) {
230 wake_up(&journal->j_wait_commit);
231 spin_unlock(&journal->j_state_lock);
Stephen Hemmingerc80544d2007-10-18 03:07:05 -0700232 wait_event(journal->j_wait_done_commit,
233 journal->j_task == NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 spin_lock(&journal->j_state_lock);
235 }
236 spin_unlock(&journal->j_state_lock);
237}
238
239/*
240 * journal_write_metadata_buffer: write a metadata buffer to the journal.
241 *
242 * Writes a metadata buffer to a given disk block. The actual IO is not
243 * performed but a new buffer_head is constructed which labels the data
244 * to be written with the correct destination disk block.
245 *
246 * Any magic-number escaping which needs to be done will cause a
247 * copy-out here. If the buffer happens to start with the
248 * JFS_MAGIC_NUMBER, then we can't write it to the log directly: the
249 * magic number is only written to the log for descripter blocks. In
250 * this case, we copy the data and replace the first word with 0, and we
251 * return a result code which indicates that this buffer needs to be
252 * marked as an escaped buffer in the corresponding log descriptor
253 * block. The missing word can then be restored when the block is read
254 * during recovery.
255 *
256 * If the source buffer has already been modified by a new transaction
257 * since we took the last commit snapshot, we use the frozen copy of
258 * that data for IO. If we end up using the existing buffer_head's data
259 * for the write, then we *have* to lock the buffer to prevent anyone
260 * else from using and possibly modifying it while the IO is in
261 * progress.
262 *
263 * The function returns a pointer to the buffer_heads to be used for IO.
264 *
265 * We assume that the journal has already been locked in this function.
266 *
267 * Return value:
268 * <0: Error
269 * >=0: Finished OK
270 *
271 * On success:
272 * Bit 0 set == escape performed on the data
273 * Bit 1 set == buffer copy-out performed (kfree the data after IO)
274 */
275
276int journal_write_metadata_buffer(transaction_t *transaction,
277 struct journal_head *jh_in,
278 struct journal_head **jh_out,
Eric Sandeen37ed3222006-09-27 01:49:31 -0700279 unsigned long blocknr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280{
281 int need_copy_out = 0;
282 int done_copy_out = 0;
283 int do_escape = 0;
284 char *mapped_data;
285 struct buffer_head *new_bh;
286 struct journal_head *new_jh;
287 struct page *new_page;
288 unsigned int new_offset;
289 struct buffer_head *bh_in = jh2bh(jh_in);
290
291 /*
292 * The buffer really shouldn't be locked: only the current committing
293 * transaction is allowed to write it, so nobody else is allowed
294 * to do any IO.
295 *
296 * akpm: except if we're journalling data, and write() output is
297 * also part of a shared mapping, and another thread has
298 * decided to launch a writepage() against this buffer.
299 */
300 J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
301
302 new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
303
304 /*
305 * If a new transaction has already done a buffer copy-out, then
306 * we use that version of the data for the commit.
307 */
308 jbd_lock_bh_state(bh_in);
309repeat:
310 if (jh_in->b_frozen_data) {
311 done_copy_out = 1;
312 new_page = virt_to_page(jh_in->b_frozen_data);
313 new_offset = offset_in_page(jh_in->b_frozen_data);
314 } else {
315 new_page = jh2bh(jh_in)->b_page;
316 new_offset = offset_in_page(jh2bh(jh_in)->b_data);
317 }
318
319 mapped_data = kmap_atomic(new_page, KM_USER0);
320 /*
321 * Check for escaping
322 */
323 if (*((__be32 *)(mapped_data + new_offset)) ==
324 cpu_to_be32(JFS_MAGIC_NUMBER)) {
325 need_copy_out = 1;
326 do_escape = 1;
327 }
328 kunmap_atomic(mapped_data, KM_USER0);
329
330 /*
331 * Do we need to do a data copy?
332 */
333 if (need_copy_out && !done_copy_out) {
334 char *tmp;
335
336 jbd_unlock_bh_state(bh_in);
Mingming Caoc089d492007-10-16 18:38:25 -0400337 tmp = jbd_alloc(bh_in->b_size, GFP_NOFS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 jbd_lock_bh_state(bh_in);
339 if (jh_in->b_frozen_data) {
Mingming Caoc089d492007-10-16 18:38:25 -0400340 jbd_free(tmp, bh_in->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 goto repeat;
342 }
343
344 jh_in->b_frozen_data = tmp;
345 mapped_data = kmap_atomic(new_page, KM_USER0);
346 memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size);
347 kunmap_atomic(mapped_data, KM_USER0);
348
349 new_page = virt_to_page(tmp);
350 new_offset = offset_in_page(tmp);
351 done_copy_out = 1;
352 }
353
354 /*
355 * Did we need to do an escaping? Now we've done all the
356 * copying, we can finally do so.
357 */
358 if (do_escape) {
359 mapped_data = kmap_atomic(new_page, KM_USER0);
360 *((unsigned int *)(mapped_data + new_offset)) = 0;
361 kunmap_atomic(mapped_data, KM_USER0);
362 }
363
364 /* keep subsequent assertions sane */
365 new_bh->b_state = 0;
366 init_buffer(new_bh, NULL, NULL);
367 atomic_set(&new_bh->b_count, 1);
368 jbd_unlock_bh_state(bh_in);
369
370 new_jh = journal_add_journal_head(new_bh); /* This sleeps */
371
372 set_bh_page(new_bh, new_page, new_offset);
373 new_jh->b_transaction = NULL;
374 new_bh->b_size = jh2bh(jh_in)->b_size;
375 new_bh->b_bdev = transaction->t_journal->j_dev;
376 new_bh->b_blocknr = blocknr;
377 set_buffer_mapped(new_bh);
378 set_buffer_dirty(new_bh);
379
380 *jh_out = new_jh;
381
382 /*
383 * The to-be-written buffer needs to get moved to the io queue,
384 * and the original buffer whose contents we are shadowing or
385 * copying is moved to the transaction's shadow queue.
386 */
387 JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
388 journal_file_buffer(jh_in, transaction, BJ_Shadow);
389 JBUFFER_TRACE(new_jh, "file as BJ_IO");
390 journal_file_buffer(new_jh, transaction, BJ_IO);
391
392 return do_escape | (done_copy_out << 1);
393}
394
395/*
396 * Allocation code for the journal file. Manage the space left in the
397 * journal, so that we can begin checkpointing when appropriate.
398 */
399
400/*
401 * __log_space_left: Return the number of free blocks left in the journal.
402 *
403 * Called with the journal already locked.
404 *
405 * Called under j_state_lock
406 */
407
408int __log_space_left(journal_t *journal)
409{
410 int left = journal->j_free;
411
412 assert_spin_locked(&journal->j_state_lock);
413
414 /*
415 * Be pessimistic here about the number of those free blocks which
416 * might be required for log descriptor control blocks.
417 */
418
419#define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */
420
421 left -= MIN_LOG_RESERVED_BLOCKS;
422
423 if (left <= 0)
424 return 0;
425 left -= (left >> 3);
426 return left;
427}
428
429/*
Jan Kara8fe4cd02009-02-11 13:04:25 -0800430 * Called under j_state_lock. Returns true if a transaction commit was started.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 */
432int __log_start_commit(journal_t *journal, tid_t target)
433{
434 /*
435 * Are we already doing a recent enough commit?
436 */
437 if (!tid_geq(journal->j_commit_request, target)) {
438 /*
439 * We want a new commit: OK, mark the request and wakup the
440 * commit thread. We do _not_ do the commit ourselves.
441 */
442
443 journal->j_commit_request = target;
444 jbd_debug(1, "JBD: requesting commit %d/%d\n",
445 journal->j_commit_request,
446 journal->j_commit_sequence);
447 wake_up(&journal->j_wait_commit);
448 return 1;
449 }
450 return 0;
451}
452
453int log_start_commit(journal_t *journal, tid_t tid)
454{
455 int ret;
456
457 spin_lock(&journal->j_state_lock);
458 ret = __log_start_commit(journal, tid);
459 spin_unlock(&journal->j_state_lock);
460 return ret;
461}
462
463/*
464 * Force and wait upon a commit if the calling process is not within
465 * transaction. This is used for forcing out undo-protected data which contains
466 * bitmaps, when the fs is running out of space.
467 *
468 * We can only force the running transaction if we don't have an active handle;
469 * otherwise, we will deadlock.
470 *
471 * Returns true if a transaction was started.
472 */
473int journal_force_commit_nested(journal_t *journal)
474{
475 transaction_t *transaction = NULL;
476 tid_t tid;
477
478 spin_lock(&journal->j_state_lock);
479 if (journal->j_running_transaction && !current->journal_info) {
480 transaction = journal->j_running_transaction;
481 __log_start_commit(journal, transaction->t_tid);
482 } else if (journal->j_committing_transaction)
483 transaction = journal->j_committing_transaction;
484
485 if (!transaction) {
486 spin_unlock(&journal->j_state_lock);
487 return 0; /* Nothing to retry */
488 }
489
490 tid = transaction->t_tid;
491 spin_unlock(&journal->j_state_lock);
492 log_wait_commit(journal, tid);
493 return 1;
494}
495
496/*
497 * Start a commit of the current running transaction (if any). Returns true
Jan Kara8fe4cd02009-02-11 13:04:25 -0800498 * if a transaction is going to be committed (or is currently already
499 * committing), and fills its tid in at *ptid
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 */
501int journal_start_commit(journal_t *journal, tid_t *ptid)
502{
503 int ret = 0;
504
505 spin_lock(&journal->j_state_lock);
506 if (journal->j_running_transaction) {
507 tid_t tid = journal->j_running_transaction->t_tid;
508
Jan Kara8fe4cd02009-02-11 13:04:25 -0800509 __log_start_commit(journal, tid);
510 /* There's a running transaction and we've just made sure
511 * it's commit has been scheduled. */
512 if (ptid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 *ptid = tid;
Jan Kara8fe4cd02009-02-11 13:04:25 -0800514 ret = 1;
515 } else if (journal->j_committing_transaction) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 /*
517 * If ext3_write_super() recently started a commit, then we
518 * have to wait for completion of that transaction
519 */
Jan Kara8fe4cd02009-02-11 13:04:25 -0800520 if (ptid)
521 *ptid = journal->j_committing_transaction->t_tid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 ret = 1;
523 }
524 spin_unlock(&journal->j_state_lock);
525 return ret;
526}
527
528/*
529 * Wait for a specified commit to complete.
530 * The caller may not hold the journal lock.
531 */
532int log_wait_commit(journal_t *journal, tid_t tid)
533{
534 int err = 0;
535
536#ifdef CONFIG_JBD_DEBUG
537 spin_lock(&journal->j_state_lock);
538 if (!tid_geq(journal->j_commit_request, tid)) {
539 printk(KERN_EMERG
540 "%s: error: j_commit_request=%d, tid=%d\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700541 __func__, journal->j_commit_request, tid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 }
543 spin_unlock(&journal->j_state_lock);
544#endif
545 spin_lock(&journal->j_state_lock);
546 while (tid_gt(tid, journal->j_commit_sequence)) {
547 jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n",
548 tid, journal->j_commit_sequence);
549 wake_up(&journal->j_wait_commit);
550 spin_unlock(&journal->j_state_lock);
551 wait_event(journal->j_wait_done_commit,
552 !tid_gt(tid, journal->j_commit_sequence));
553 spin_lock(&journal->j_state_lock);
554 }
555 spin_unlock(&journal->j_state_lock);
556
557 if (unlikely(is_journal_aborted(journal))) {
558 printk(KERN_EMERG "journal commit I/O error\n");
559 err = -EIO;
560 }
561 return err;
562}
563
564/*
565 * Log buffer allocation routines:
566 */
567
568int journal_next_log_block(journal_t *journal, unsigned long *retp)
569{
570 unsigned long blocknr;
571
572 spin_lock(&journal->j_state_lock);
573 J_ASSERT(journal->j_free > 1);
574
575 blocknr = journal->j_head;
576 journal->j_head++;
577 journal->j_free--;
578 if (journal->j_head == journal->j_last)
579 journal->j_head = journal->j_first;
580 spin_unlock(&journal->j_state_lock);
581 return journal_bmap(journal, blocknr, retp);
582}
583
584/*
585 * Conversion of logical to physical block numbers for the journal
586 *
587 * On external journals the journal blocks are identity-mapped, so
588 * this is a no-op. If needed, we can use j_blk_offset - everything is
589 * ready.
590 */
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700591int journal_bmap(journal_t *journal, unsigned long blocknr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 unsigned long *retp)
593{
594 int err = 0;
595 unsigned long ret;
596
597 if (journal->j_inode) {
598 ret = bmap(journal->j_inode, blocknr);
599 if (ret)
600 *retp = ret;
601 else {
602 char b[BDEVNAME_SIZE];
603
604 printk(KERN_ALERT "%s: journal block not found "
605 "at offset %lu on %s\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700606 __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 blocknr,
608 bdevname(journal->j_dev, b));
609 err = -EIO;
610 __journal_abort_soft(journal, err);
611 }
612 } else {
613 *retp = blocknr; /* +journal->j_blk_offset */
614 }
615 return err;
616}
617
618/*
619 * We play buffer_head aliasing tricks to write data/metadata blocks to
620 * the journal without copying their contents, but for journal
621 * descriptor blocks we do need to generate bona fide buffers.
622 *
623 * After the caller of journal_get_descriptor_buffer() has finished modifying
624 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
625 * But we don't bother doing that, so there will be coherency problems with
626 * mmaps of blockdevs which hold live JBD-controlled filesystems.
627 */
628struct journal_head *journal_get_descriptor_buffer(journal_t *journal)
629{
630 struct buffer_head *bh;
631 unsigned long blocknr;
632 int err;
633
634 err = journal_next_log_block(journal, &blocknr);
635
636 if (err)
637 return NULL;
638
639 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
Jan Karaecca9af2009-04-02 16:57:13 -0700640 if (!bh)
641 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642 lock_buffer(bh);
643 memset(bh->b_data, 0, journal->j_blocksize);
644 set_buffer_uptodate(bh);
645 unlock_buffer(bh);
646 BUFFER_TRACE(bh, "return this buffer");
647 return journal_add_journal_head(bh);
648}
649
650/*
651 * Management for journal control blocks: functions to create and
652 * destroy journal_t structures, and to initialise and read existing
653 * journal blocks from disk. */
654
655/* First: create and setup a journal_t object in memory. We initialise
656 * very few fields yet: that has to wait until we have created the
657 * journal structures from from scratch, or loaded them from disk. */
658
659static journal_t * journal_init_common (void)
660{
661 journal_t *journal;
662 int err;
663
Mingming Cao8c3478a2007-10-18 23:39:20 -0700664 journal = kzalloc(sizeof(*journal), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 if (!journal)
666 goto fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667
668 init_waitqueue_head(&journal->j_wait_transaction_locked);
669 init_waitqueue_head(&journal->j_wait_logspace);
670 init_waitqueue_head(&journal->j_wait_done_commit);
671 init_waitqueue_head(&journal->j_wait_checkpoint);
672 init_waitqueue_head(&journal->j_wait_commit);
673 init_waitqueue_head(&journal->j_wait_updates);
Arjan van de Ven2c68ee72006-03-23 03:00:35 -0800674 mutex_init(&journal->j_barrier);
675 mutex_init(&journal->j_checkpoint_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 spin_lock_init(&journal->j_revoke_lock);
677 spin_lock_init(&journal->j_list_lock);
678 spin_lock_init(&journal->j_state_lock);
679
680 journal->j_commit_interval = (HZ * JBD_DEFAULT_MAX_COMMIT_AGE);
681
682 /* The journal is marked for error until we succeed with recovery! */
683 journal->j_flags = JFS_ABORT;
684
685 /* Set up a default-sized revoke table for the new mount. */
686 err = journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
687 if (err) {
688 kfree(journal);
689 goto fail;
690 }
691 return journal;
692fail:
693 return NULL;
694}
695
696/* journal_init_dev and journal_init_inode:
697 *
698 * Create a journal structure assigned some fixed set of disk blocks to
699 * the journal. We don't actually touch those disk blocks yet, but we
700 * need to set up all of the mapping information to tell the journaling
701 * system where the journal blocks are.
702 *
703 */
704
705/**
Randy Dunlap0cf01f62008-03-19 17:00:44 -0700706 * journal_t * journal_init_dev() - creates and initialises a journal structure
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 * @bdev: Block device on which to create the journal
708 * @fs_dev: Device which hold journalled filesystem for this journal.
709 * @start: Block nr Start of journal.
Eric Sandeen37ed3222006-09-27 01:49:31 -0700710 * @len: Length of the journal in blocks.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 * @blocksize: blocksize of journalling device
Randy Dunlap0cf01f62008-03-19 17:00:44 -0700712 *
713 * Returns: a newly created journal_t *
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700714 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 * journal_init_dev creates a journal which maps a fixed contiguous
716 * range of blocks on an arbitrary block device.
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700717 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 */
719journal_t * journal_init_dev(struct block_device *bdev,
720 struct block_device *fs_dev,
721 int start, int len, int blocksize)
722{
723 journal_t *journal = journal_init_common();
724 struct buffer_head *bh;
725 int n;
726
727 if (!journal)
728 return NULL;
729
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 /* journal descriptor can store up to n blocks -bzzz */
Zoltan Menyhartd1807792006-09-29 01:58:40 -0700731 journal->j_blocksize = blocksize;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 n = journal->j_blocksize / sizeof(journal_block_tag_t);
733 journal->j_wbufsize = n;
734 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
735 if (!journal->j_wbuf) {
736 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700737 __func__);
Jan Karaecca9af2009-04-02 16:57:13 -0700738 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 }
Zoltan Menyhartd1807792006-09-29 01:58:40 -0700740 journal->j_dev = bdev;
741 journal->j_fs_dev = fs_dev;
742 journal->j_blk_offset = start;
743 journal->j_maxlen = len;
744
745 bh = __getblk(journal->j_dev, start, journal->j_blocksize);
Jan Karaecca9af2009-04-02 16:57:13 -0700746 if (!bh) {
747 printk(KERN_ERR
748 "%s: Cannot get buffer for journal superblock\n",
749 __func__);
750 goto out_err;
751 }
Zoltan Menyhartd1807792006-09-29 01:58:40 -0700752 journal->j_sb_buffer = bh;
753 journal->j_superblock = (journal_superblock_t *)bh->b_data;
Jan Karaecca9af2009-04-02 16:57:13 -0700754
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755 return journal;
Jan Karaecca9af2009-04-02 16:57:13 -0700756out_err:
757 kfree(journal);
758 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759}
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700760
761/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 * journal_t * journal_init_inode () - creates a journal which maps to a inode.
763 * @inode: An inode to create the journal in
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700764 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 * journal_init_inode creates a journal which maps an on-disk inode as
766 * the journal. The inode must exist already, must support bmap() and
767 * must have all data blocks preallocated.
768 */
769journal_t * journal_init_inode (struct inode *inode)
770{
771 struct buffer_head *bh;
772 journal_t *journal = journal_init_common();
773 int err;
774 int n;
775 unsigned long blocknr;
776
777 if (!journal)
778 return NULL;
779
780 journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
781 journal->j_inode = inode;
782 jbd_debug(1,
783 "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700784 journal, inode->i_sb->s_id, inode->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785 (long long) inode->i_size,
786 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
787
788 journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
789 journal->j_blocksize = inode->i_sb->s_blocksize;
790
791 /* journal descriptor can store up to n blocks -bzzz */
792 n = journal->j_blocksize / sizeof(journal_block_tag_t);
793 journal->j_wbufsize = n;
794 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
795 if (!journal->j_wbuf) {
796 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700797 __func__);
Jan Karaecca9af2009-04-02 16:57:13 -0700798 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 }
800
801 err = journal_bmap(journal, 0, &blocknr);
802 /* If that failed, give up */
803 if (err) {
804 printk(KERN_ERR "%s: Cannnot locate journal superblock\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700805 __func__);
Jan Karaecca9af2009-04-02 16:57:13 -0700806 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 }
808
809 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
Jan Karaecca9af2009-04-02 16:57:13 -0700810 if (!bh) {
811 printk(KERN_ERR
812 "%s: Cannot get buffer for journal superblock\n",
813 __func__);
814 goto out_err;
815 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 journal->j_sb_buffer = bh;
817 journal->j_superblock = (journal_superblock_t *)bh->b_data;
818
819 return journal;
Jan Karaecca9af2009-04-02 16:57:13 -0700820out_err:
821 kfree(journal);
822 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823}
824
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700825/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 * If the journal init or create aborts, we need to mark the journal
827 * superblock as being NULL to prevent the journal destroy from writing
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700828 * back a bogus superblock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 */
830static void journal_fail_superblock (journal_t *journal)
831{
832 struct buffer_head *bh = journal->j_sb_buffer;
833 brelse(bh);
834 journal->j_sb_buffer = NULL;
835}
836
837/*
838 * Given a journal_t structure, initialise the various fields for
839 * startup of a new journaling session. We use this both when creating
840 * a journal, and after recovering an old journal to reset it for
841 * subsequent use.
842 */
843
844static int journal_reset(journal_t *journal)
845{
846 journal_superblock_t *sb = journal->j_superblock;
Eric Sandeen37ed3222006-09-27 01:49:31 -0700847 unsigned long first, last;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848
849 first = be32_to_cpu(sb->s_first);
850 last = be32_to_cpu(sb->s_maxlen);
851
852 journal->j_first = first;
853 journal->j_last = last;
854
855 journal->j_head = first;
856 journal->j_tail = first;
857 journal->j_free = last - first;
858
859 journal->j_tail_sequence = journal->j_transaction_sequence;
860 journal->j_commit_sequence = journal->j_transaction_sequence - 1;
861 journal->j_commit_request = journal->j_commit_sequence;
862
863 journal->j_max_transaction_buffers = journal->j_maxlen / 4;
864
865 /* Add the dynamic fields and write it to disk. */
866 journal_update_superblock(journal, 1);
Pavel Emelianov97f06782007-05-08 00:30:42 -0700867 return journal_start_thread(journal);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868}
869
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700870/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871 * int journal_create() - Initialise the new journal file
872 * @journal: Journal to create. This structure must have been initialised
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700873 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874 * Given a journal_t structure which tells us which disk blocks we can
875 * use, create a new journal superblock and initialise all of the
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700876 * journal fields from scratch.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 **/
878int journal_create(journal_t *journal)
879{
880 unsigned long blocknr;
881 struct buffer_head *bh;
882 journal_superblock_t *sb;
883 int i, err;
884
885 if (journal->j_maxlen < JFS_MIN_JOURNAL_BLOCKS) {
886 printk (KERN_ERR "Journal length (%d blocks) too short.\n",
887 journal->j_maxlen);
888 journal_fail_superblock(journal);
889 return -EINVAL;
890 }
891
892 if (journal->j_inode == NULL) {
893 /*
894 * We don't know what block to start at!
895 */
896 printk(KERN_EMERG
897 "%s: creation of journal on external device!\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700898 __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 BUG();
900 }
901
902 /* Zero out the entire journal on disk. We cannot afford to
903 have any blocks on disk beginning with JFS_MAGIC_NUMBER. */
904 jbd_debug(1, "JBD: Zeroing out journal blocks...\n");
905 for (i = 0; i < journal->j_maxlen; i++) {
906 err = journal_bmap(journal, i, &blocknr);
907 if (err)
908 return err;
909 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
910 lock_buffer(bh);
911 memset (bh->b_data, 0, journal->j_blocksize);
912 BUFFER_TRACE(bh, "marking dirty");
913 mark_buffer_dirty(bh);
914 BUFFER_TRACE(bh, "marking uptodate");
915 set_buffer_uptodate(bh);
916 unlock_buffer(bh);
917 __brelse(bh);
918 }
919
920 sync_blockdev(journal->j_dev);
921 jbd_debug(1, "JBD: journal cleared.\n");
922
923 /* OK, fill in the initial static fields in the new superblock */
924 sb = journal->j_superblock;
925
926 sb->s_header.h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
927 sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2);
928
929 sb->s_blocksize = cpu_to_be32(journal->j_blocksize);
930 sb->s_maxlen = cpu_to_be32(journal->j_maxlen);
931 sb->s_first = cpu_to_be32(1);
932
933 journal->j_transaction_sequence = 1;
934
935 journal->j_flags &= ~JFS_ABORT;
936 journal->j_format_version = 2;
937
938 return journal_reset(journal);
939}
940
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700941/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 * void journal_update_superblock() - Update journal sb on disk.
943 * @journal: The journal to update.
944 * @wait: Set to '0' if you don't want to wait for IO completion.
945 *
946 * Update a journal's dynamic superblock fields and write it to disk,
947 * optionally waiting for the IO to complete.
948 */
949void journal_update_superblock(journal_t *journal, int wait)
950{
951 journal_superblock_t *sb = journal->j_superblock;
952 struct buffer_head *bh = journal->j_sb_buffer;
953
954 /*
955 * As a special case, if the on-disk copy is already marked as needing
956 * no recovery (s_start == 0) and there are no outstanding transactions
957 * in the filesystem, then we can safely defer the superblock update
958 * until the next commit by setting JFS_FLUSHED. This avoids
959 * attempting a write to a potential-readonly device.
960 */
961 if (sb->s_start == 0 && journal->j_tail_sequence ==
962 journal->j_transaction_sequence) {
963 jbd_debug(1,"JBD: Skipping superblock update on recovered sb "
964 "(start %ld, seq %d, errno %d)\n",
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700965 journal->j_tail, journal->j_tail_sequence,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 journal->j_errno);
967 goto out;
968 }
969
970 spin_lock(&journal->j_state_lock);
971 jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n",
972 journal->j_tail, journal->j_tail_sequence, journal->j_errno);
973
974 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
975 sb->s_start = cpu_to_be32(journal->j_tail);
976 sb->s_errno = cpu_to_be32(journal->j_errno);
977 spin_unlock(&journal->j_state_lock);
978
979 BUFFER_TRACE(bh, "marking dirty");
980 mark_buffer_dirty(bh);
981 if (wait)
982 sync_dirty_buffer(bh);
983 else
Jan Kara26707692005-09-06 15:19:12 -0700984 ll_rw_block(SWRITE, 1, &bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985
986out:
987 /* If we have just flushed the log (by marking s_start==0), then
988 * any future commit will have to be careful to update the
989 * superblock again to re-record the true start of the log. */
990
991 spin_lock(&journal->j_state_lock);
992 if (sb->s_start)
993 journal->j_flags &= ~JFS_FLUSHED;
994 else
995 journal->j_flags |= JFS_FLUSHED;
996 spin_unlock(&journal->j_state_lock);
997}
998
999/*
1000 * Read the superblock for a given journal, performing initial
1001 * validation of the format.
1002 */
1003
1004static int journal_get_superblock(journal_t *journal)
1005{
1006 struct buffer_head *bh;
1007 journal_superblock_t *sb;
1008 int err = -EIO;
1009
1010 bh = journal->j_sb_buffer;
1011
1012 J_ASSERT(bh != NULL);
1013 if (!buffer_uptodate(bh)) {
1014 ll_rw_block(READ, 1, &bh);
1015 wait_on_buffer(bh);
1016 if (!buffer_uptodate(bh)) {
1017 printk (KERN_ERR
1018 "JBD: IO error reading journal superblock\n");
1019 goto out;
1020 }
1021 }
1022
1023 sb = journal->j_superblock;
1024
1025 err = -EINVAL;
1026
1027 if (sb->s_header.h_magic != cpu_to_be32(JFS_MAGIC_NUMBER) ||
1028 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1029 printk(KERN_WARNING "JBD: no valid journal superblock found\n");
1030 goto out;
1031 }
1032
1033 switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1034 case JFS_SUPERBLOCK_V1:
1035 journal->j_format_version = 1;
1036 break;
1037 case JFS_SUPERBLOCK_V2:
1038 journal->j_format_version = 2;
1039 break;
1040 default:
1041 printk(KERN_WARNING "JBD: unrecognised superblock format ID\n");
1042 goto out;
1043 }
1044
1045 if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
1046 journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
1047 else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
1048 printk (KERN_WARNING "JBD: journal file too short\n");
1049 goto out;
1050 }
1051
1052 return 0;
1053
1054out:
1055 journal_fail_superblock(journal);
1056 return err;
1057}
1058
1059/*
1060 * Load the on-disk journal superblock and read the key fields into the
1061 * journal_t.
1062 */
1063
1064static int load_superblock(journal_t *journal)
1065{
1066 int err;
1067 journal_superblock_t *sb;
1068
1069 err = journal_get_superblock(journal);
1070 if (err)
1071 return err;
1072
1073 sb = journal->j_superblock;
1074
1075 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1076 journal->j_tail = be32_to_cpu(sb->s_start);
1077 journal->j_first = be32_to_cpu(sb->s_first);
1078 journal->j_last = be32_to_cpu(sb->s_maxlen);
1079 journal->j_errno = be32_to_cpu(sb->s_errno);
1080
1081 return 0;
1082}
1083
1084
1085/**
1086 * int journal_load() - Read journal from disk.
1087 * @journal: Journal to act on.
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001088 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 * Given a journal_t structure which tells us which disk blocks contain
1090 * a journal, read the journal from disk to initialise the in-memory
1091 * structures.
1092 */
1093int journal_load(journal_t *journal)
1094{
1095 int err;
Badari Pulavartyea817392006-08-27 01:23:52 -07001096 journal_superblock_t *sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097
1098 err = load_superblock(journal);
1099 if (err)
1100 return err;
1101
Badari Pulavartyea817392006-08-27 01:23:52 -07001102 sb = journal->j_superblock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103 /* If this is a V2 superblock, then we have to check the
1104 * features flags on it. */
1105
1106 if (journal->j_format_version >= 2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107 if ((sb->s_feature_ro_compat &
1108 ~cpu_to_be32(JFS_KNOWN_ROCOMPAT_FEATURES)) ||
1109 (sb->s_feature_incompat &
1110 ~cpu_to_be32(JFS_KNOWN_INCOMPAT_FEATURES))) {
1111 printk (KERN_WARNING
1112 "JBD: Unrecognised features on journal\n");
1113 return -EINVAL;
1114 }
1115 }
1116
1117 /* Let the recovery code check whether it needs to recover any
1118 * data from the journal. */
1119 if (journal_recover(journal))
1120 goto recovery_error;
1121
1122 /* OK, we've finished with the dynamic journal bits:
1123 * reinitialise the dynamic contents of the superblock in memory
1124 * and reset them on disk. */
1125 if (journal_reset(journal))
1126 goto recovery_error;
1127
1128 journal->j_flags &= ~JFS_ABORT;
1129 journal->j_flags |= JFS_LOADED;
1130 return 0;
1131
1132recovery_error:
1133 printk (KERN_WARNING "JBD: recovery failed\n");
1134 return -EIO;
1135}
1136
1137/**
1138 * void journal_destroy() - Release a journal_t structure.
1139 * @journal: Journal to act on.
1140 *
1141 * Release a journal_t structure once it is no longer in use by the
1142 * journaled object.
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001143 * Return <0 if we couldn't clean up the journal.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144 */
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001145int journal_destroy(journal_t *journal)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146{
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001147 int err = 0;
1148
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 /* Wait for the commit thread to wake up and die. */
1150 journal_kill_thread(journal);
1151
1152 /* Force a final log commit */
1153 if (journal->j_running_transaction)
1154 journal_commit_transaction(journal);
1155
1156 /* Force any old transactions to disk */
1157
1158 /* Totally anal locking here... */
1159 spin_lock(&journal->j_list_lock);
1160 while (journal->j_checkpoint_transactions != NULL) {
1161 spin_unlock(&journal->j_list_lock);
1162 log_do_checkpoint(journal);
1163 spin_lock(&journal->j_list_lock);
1164 }
1165
1166 J_ASSERT(journal->j_running_transaction == NULL);
1167 J_ASSERT(journal->j_committing_transaction == NULL);
1168 J_ASSERT(journal->j_checkpoint_transactions == NULL);
1169 spin_unlock(&journal->j_list_lock);
1170
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 if (journal->j_sb_buffer) {
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001172 if (!is_journal_aborted(journal)) {
1173 /* We can now mark the journal as empty. */
1174 journal->j_tail = 0;
1175 journal->j_tail_sequence =
1176 ++journal->j_transaction_sequence;
1177 journal_update_superblock(journal, 1);
1178 } else {
1179 err = -EIO;
1180 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181 brelse(journal->j_sb_buffer);
1182 }
1183
1184 if (journal->j_inode)
1185 iput(journal->j_inode);
1186 if (journal->j_revoke)
1187 journal_destroy_revoke(journal);
1188 kfree(journal->j_wbuf);
1189 kfree(journal);
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001190
1191 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192}
1193
1194
1195/**
1196 *int journal_check_used_features () - Check if features specified are used.
1197 * @journal: Journal to check.
1198 * @compat: bitmask of compatible features
1199 * @ro: bitmask of features that force read-only mount
1200 * @incompat: bitmask of incompatible features
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001201 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 * Check whether the journal uses all of a given set of
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001203 * features. Return true (non-zero) if it does.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 **/
1205
1206int journal_check_used_features (journal_t *journal, unsigned long compat,
1207 unsigned long ro, unsigned long incompat)
1208{
1209 journal_superblock_t *sb;
1210
1211 if (!compat && !ro && !incompat)
1212 return 1;
1213 if (journal->j_format_version == 1)
1214 return 0;
1215
1216 sb = journal->j_superblock;
1217
1218 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
1219 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
1220 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
1221 return 1;
1222
1223 return 0;
1224}
1225
1226/**
1227 * int journal_check_available_features() - Check feature set in journalling layer
1228 * @journal: Journal to check.
1229 * @compat: bitmask of compatible features
1230 * @ro: bitmask of features that force read-only mount
1231 * @incompat: bitmask of incompatible features
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001232 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233 * Check whether the journaling code supports the use of
1234 * all of a given set of features on this journal. Return true
1235 * (non-zero) if it can. */
1236
1237int journal_check_available_features (journal_t *journal, unsigned long compat,
1238 unsigned long ro, unsigned long incompat)
1239{
1240 journal_superblock_t *sb;
1241
1242 if (!compat && !ro && !incompat)
1243 return 1;
1244
1245 sb = journal->j_superblock;
1246
1247 /* We can support any known requested features iff the
1248 * superblock is in version 2. Otherwise we fail to support any
1249 * extended sb features. */
1250
1251 if (journal->j_format_version != 2)
1252 return 0;
1253
1254 if ((compat & JFS_KNOWN_COMPAT_FEATURES) == compat &&
1255 (ro & JFS_KNOWN_ROCOMPAT_FEATURES) == ro &&
1256 (incompat & JFS_KNOWN_INCOMPAT_FEATURES) == incompat)
1257 return 1;
1258
1259 return 0;
1260}
1261
1262/**
1263 * int journal_set_features () - Mark a given journal feature in the superblock
1264 * @journal: Journal to act on.
1265 * @compat: bitmask of compatible features
1266 * @ro: bitmask of features that force read-only mount
1267 * @incompat: bitmask of incompatible features
1268 *
1269 * Mark a given journal feature as present on the
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001270 * superblock. Returns true if the requested features could be set.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 *
1272 */
1273
1274int journal_set_features (journal_t *journal, unsigned long compat,
1275 unsigned long ro, unsigned long incompat)
1276{
1277 journal_superblock_t *sb;
1278
1279 if (journal_check_used_features(journal, compat, ro, incompat))
1280 return 1;
1281
1282 if (!journal_check_available_features(journal, compat, ro, incompat))
1283 return 0;
1284
1285 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1286 compat, ro, incompat);
1287
1288 sb = journal->j_superblock;
1289
1290 sb->s_feature_compat |= cpu_to_be32(compat);
1291 sb->s_feature_ro_compat |= cpu_to_be32(ro);
1292 sb->s_feature_incompat |= cpu_to_be32(incompat);
1293
1294 return 1;
1295}
1296
1297
1298/**
1299 * int journal_update_format () - Update on-disk journal structure.
1300 * @journal: Journal to act on.
1301 *
1302 * Given an initialised but unloaded journal struct, poke about in the
1303 * on-disk structure to update it to the most recent supported version.
1304 */
1305int journal_update_format (journal_t *journal)
1306{
1307 journal_superblock_t *sb;
1308 int err;
1309
1310 err = journal_get_superblock(journal);
1311 if (err)
1312 return err;
1313
1314 sb = journal->j_superblock;
1315
1316 switch (be32_to_cpu(sb->s_header.h_blocktype)) {
1317 case JFS_SUPERBLOCK_V2:
1318 return 0;
1319 case JFS_SUPERBLOCK_V1:
1320 return journal_convert_superblock_v1(journal, sb);
1321 default:
1322 break;
1323 }
1324 return -EINVAL;
1325}
1326
1327static int journal_convert_superblock_v1(journal_t *journal,
1328 journal_superblock_t *sb)
1329{
1330 int offset, blocksize;
1331 struct buffer_head *bh;
1332
1333 printk(KERN_WARNING
1334 "JBD: Converting superblock from version 1 to 2.\n");
1335
1336 /* Pre-initialise new fields to zero */
1337 offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
1338 blocksize = be32_to_cpu(sb->s_blocksize);
1339 memset(&sb->s_feature_compat, 0, blocksize-offset);
1340
1341 sb->s_nr_users = cpu_to_be32(1);
1342 sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2);
1343 journal->j_format_version = 2;
1344
1345 bh = journal->j_sb_buffer;
1346 BUFFER_TRACE(bh, "marking dirty");
1347 mark_buffer_dirty(bh);
1348 sync_dirty_buffer(bh);
1349 return 0;
1350}
1351
1352
1353/**
1354 * int journal_flush () - Flush journal
1355 * @journal: Journal to act on.
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001356 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001357 * Flush all data for a given journal to disk and empty the journal.
1358 * Filesystems can use this when remounting readonly to ensure that
1359 * recovery does not need to happen on remount.
1360 */
1361
1362int journal_flush(journal_t *journal)
1363{
1364 int err = 0;
1365 transaction_t *transaction = NULL;
1366 unsigned long old_tail;
1367
1368 spin_lock(&journal->j_state_lock);
1369
1370 /* Force everything buffered to the log... */
1371 if (journal->j_running_transaction) {
1372 transaction = journal->j_running_transaction;
1373 __log_start_commit(journal, transaction->t_tid);
1374 } else if (journal->j_committing_transaction)
1375 transaction = journal->j_committing_transaction;
1376
1377 /* Wait for the log commit to complete... */
1378 if (transaction) {
1379 tid_t tid = transaction->t_tid;
1380
1381 spin_unlock(&journal->j_state_lock);
1382 log_wait_commit(journal, tid);
1383 } else {
1384 spin_unlock(&journal->j_state_lock);
1385 }
1386
1387 /* ...and flush everything in the log out to disk. */
1388 spin_lock(&journal->j_list_lock);
1389 while (!err && journal->j_checkpoint_transactions != NULL) {
1390 spin_unlock(&journal->j_list_lock);
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001391 mutex_lock(&journal->j_checkpoint_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392 err = log_do_checkpoint(journal);
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001393 mutex_unlock(&journal->j_checkpoint_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394 spin_lock(&journal->j_list_lock);
1395 }
1396 spin_unlock(&journal->j_list_lock);
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001397
1398 if (is_journal_aborted(journal))
1399 return -EIO;
1400
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401 cleanup_journal_tail(journal);
1402
1403 /* Finally, mark the journal as really needing no recovery.
1404 * This sets s_start==0 in the underlying superblock, which is
1405 * the magic code for a fully-recovered superblock. Any future
1406 * commits of data to the journal will restore the current
1407 * s_start value. */
1408 spin_lock(&journal->j_state_lock);
1409 old_tail = journal->j_tail;
1410 journal->j_tail = 0;
1411 spin_unlock(&journal->j_state_lock);
1412 journal_update_superblock(journal, 1);
1413 spin_lock(&journal->j_state_lock);
1414 journal->j_tail = old_tail;
1415
1416 J_ASSERT(!journal->j_running_transaction);
1417 J_ASSERT(!journal->j_committing_transaction);
1418 J_ASSERT(!journal->j_checkpoint_transactions);
1419 J_ASSERT(journal->j_head == journal->j_tail);
1420 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
1421 spin_unlock(&journal->j_state_lock);
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001422 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423}
1424
1425/**
1426 * int journal_wipe() - Wipe journal contents
1427 * @journal: Journal to act on.
1428 * @write: flag (see below)
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001429 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430 * Wipe out all of the contents of a journal, safely. This will produce
1431 * a warning if the journal contains any valid recovery information.
1432 * Must be called between journal_init_*() and journal_load().
1433 *
1434 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
1435 * we merely suppress recovery.
1436 */
1437
1438int journal_wipe(journal_t *journal, int write)
1439{
1440 journal_superblock_t *sb;
1441 int err = 0;
1442
1443 J_ASSERT (!(journal->j_flags & JFS_LOADED));
1444
1445 err = load_superblock(journal);
1446 if (err)
1447 return err;
1448
1449 sb = journal->j_superblock;
1450
1451 if (!journal->j_tail)
1452 goto no_recovery;
1453
1454 printk (KERN_WARNING "JBD: %s recovery information on journal\n",
1455 write ? "Clearing" : "Ignoring");
1456
1457 err = journal_skip_recovery(journal);
1458 if (write)
1459 journal_update_superblock(journal, 1);
1460
1461 no_recovery:
1462 return err;
1463}
1464
1465/*
1466 * journal_dev_name: format a character string to describe on what
1467 * device this journal is present.
1468 */
1469
Adrian Bunk022a4a72005-09-06 15:16:41 -07001470static const char *journal_dev_name(journal_t *journal, char *buffer)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471{
1472 struct block_device *bdev;
1473
1474 if (journal->j_inode)
1475 bdev = journal->j_inode->i_sb->s_bdev;
1476 else
1477 bdev = journal->j_dev;
1478
1479 return bdevname(bdev, buffer);
1480}
1481
1482/*
1483 * Journal abort has very specific semantics, which we describe
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001484 * for journal abort.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485 *
1486 * Two internal function, which provide abort to te jbd layer
1487 * itself are here.
1488 */
1489
1490/*
1491 * Quick version for internal journal use (doesn't lock the journal).
1492 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
1493 * and don't attempt to make any other journal updates.
1494 */
Adrian Bunk53308382008-02-06 01:40:12 -08001495static void __journal_abort_hard(journal_t *journal)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496{
1497 transaction_t *transaction;
1498 char b[BDEVNAME_SIZE];
1499
1500 if (journal->j_flags & JFS_ABORT)
1501 return;
1502
1503 printk(KERN_ERR "Aborting journal on device %s.\n",
1504 journal_dev_name(journal, b));
1505
1506 spin_lock(&journal->j_state_lock);
1507 journal->j_flags |= JFS_ABORT;
1508 transaction = journal->j_running_transaction;
1509 if (transaction)
1510 __log_start_commit(journal, transaction->t_tid);
1511 spin_unlock(&journal->j_state_lock);
1512}
1513
1514/* Soft abort: record the abort error status in the journal superblock,
1515 * but don't do any other IO. */
Adrian Bunk022a4a72005-09-06 15:16:41 -07001516static void __journal_abort_soft (journal_t *journal, int errno)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001517{
1518 if (journal->j_flags & JFS_ABORT)
1519 return;
1520
1521 if (!journal->j_errno)
1522 journal->j_errno = errno;
1523
1524 __journal_abort_hard(journal);
1525
1526 if (errno)
1527 journal_update_superblock(journal, 1);
1528}
1529
1530/**
1531 * void journal_abort () - Shutdown the journal immediately.
1532 * @journal: the journal to shutdown.
1533 * @errno: an error number to record in the journal indicating
1534 * the reason for the shutdown.
1535 *
1536 * Perform a complete, immediate shutdown of the ENTIRE
1537 * journal (not of a single transaction). This operation cannot be
1538 * undone without closing and reopening the journal.
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001539 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540 * The journal_abort function is intended to support higher level error
1541 * recovery mechanisms such as the ext2/ext3 remount-readonly error
1542 * mode.
1543 *
1544 * Journal abort has very specific semantics. Any existing dirty,
1545 * unjournaled buffers in the main filesystem will still be written to
1546 * disk by bdflush, but the journaling mechanism will be suspended
1547 * immediately and no further transaction commits will be honoured.
1548 *
1549 * Any dirty, journaled buffers will be written back to disk without
1550 * hitting the journal. Atomicity cannot be guaranteed on an aborted
1551 * filesystem, but we _do_ attempt to leave as much data as possible
1552 * behind for fsck to use for cleanup.
1553 *
1554 * Any attempt to get a new transaction handle on a journal which is in
1555 * ABORT state will just result in an -EROFS error return. A
1556 * journal_stop on an existing handle will return -EIO if we have
1557 * entered abort state during the update.
1558 *
1559 * Recursive transactions are not disturbed by journal abort until the
1560 * final journal_stop, which will receive the -EIO error.
1561 *
1562 * Finally, the journal_abort call allows the caller to supply an errno
1563 * which will be recorded (if possible) in the journal superblock. This
1564 * allows a client to record failure conditions in the middle of a
1565 * transaction without having to complete the transaction to record the
1566 * failure to disk. ext3_error, for example, now uses this
1567 * functionality.
1568 *
1569 * Errors which originate from within the journaling layer will NOT
1570 * supply an errno; a null errno implies that absolutely no further
1571 * writes are done to the journal (unless there are any already in
1572 * progress).
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001573 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001574 */
1575
1576void journal_abort(journal_t *journal, int errno)
1577{
1578 __journal_abort_soft(journal, errno);
1579}
1580
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001581/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001582 * int journal_errno () - returns the journal's error state.
1583 * @journal: journal to examine.
1584 *
1585 * This is the errno numbet set with journal_abort(), the last
1586 * time the journal was mounted - if the journal was stopped
1587 * without calling abort this will be 0.
1588 *
1589 * If the journal has been aborted on this mount time -EROFS will
1590 * be returned.
1591 */
1592int journal_errno(journal_t *journal)
1593{
1594 int err;
1595
1596 spin_lock(&journal->j_state_lock);
1597 if (journal->j_flags & JFS_ABORT)
1598 err = -EROFS;
1599 else
1600 err = journal->j_errno;
1601 spin_unlock(&journal->j_state_lock);
1602 return err;
1603}
1604
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001605/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001606 * int journal_clear_err () - clears the journal's error state
1607 * @journal: journal to act on.
1608 *
1609 * An error must be cleared or Acked to take a FS out of readonly
1610 * mode.
1611 */
1612int journal_clear_err(journal_t *journal)
1613{
1614 int err = 0;
1615
1616 spin_lock(&journal->j_state_lock);
1617 if (journal->j_flags & JFS_ABORT)
1618 err = -EROFS;
1619 else
1620 journal->j_errno = 0;
1621 spin_unlock(&journal->j_state_lock);
1622 return err;
1623}
1624
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001625/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001626 * void journal_ack_err() - Ack journal err.
1627 * @journal: journal to act on.
1628 *
1629 * An error must be cleared or Acked to take a FS out of readonly
1630 * mode.
1631 */
1632void journal_ack_err(journal_t *journal)
1633{
1634 spin_lock(&journal->j_state_lock);
1635 if (journal->j_errno)
1636 journal->j_flags |= JFS_ACK_ERR;
1637 spin_unlock(&journal->j_state_lock);
1638}
1639
1640int journal_blocks_per_page(struct inode *inode)
1641{
1642 return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
1643}
1644
1645/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646 * Journal_head storage management
1647 */
Christoph Lametere18b8902006-12-06 20:33:20 -08001648static struct kmem_cache *journal_head_cache;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001649#ifdef CONFIG_JBD_DEBUG
1650static atomic_t nr_journal_heads = ATOMIC_INIT(0);
1651#endif
1652
1653static int journal_init_journal_head_cache(void)
1654{
1655 int retval;
1656
Al Viro1076d172008-03-29 03:07:18 +00001657 J_ASSERT(journal_head_cache == NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001658 journal_head_cache = kmem_cache_create("journal_head",
1659 sizeof(struct journal_head),
1660 0, /* offset */
Mel Gormane12ba742007-10-16 01:25:52 -07001661 SLAB_TEMPORARY, /* flags */
Paul Mundt20c2df82007-07-20 10:11:58 +09001662 NULL); /* ctor */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663 retval = 0;
Al Viro1076d172008-03-29 03:07:18 +00001664 if (!journal_head_cache) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001665 retval = -ENOMEM;
1666 printk(KERN_EMERG "JBD: no memory for journal_head cache\n");
1667 }
1668 return retval;
1669}
1670
1671static void journal_destroy_journal_head_cache(void)
1672{
Duane Griffin3850f7a2008-07-25 01:46:19 -07001673 if (journal_head_cache) {
1674 kmem_cache_destroy(journal_head_cache);
1675 journal_head_cache = NULL;
1676 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677}
1678
1679/*
1680 * journal_head splicing and dicing
1681 */
1682static struct journal_head *journal_alloc_journal_head(void)
1683{
1684 struct journal_head *ret;
1685 static unsigned long last_warning;
1686
1687#ifdef CONFIG_JBD_DEBUG
1688 atomic_inc(&nr_journal_heads);
1689#endif
1690 ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS);
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001691 if (ret == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001692 jbd_debug(1, "out of memory for journal_head\n");
1693 if (time_after(jiffies, last_warning + 5*HZ)) {
1694 printk(KERN_NOTICE "ENOMEM in %s, retrying.\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -07001695 __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001696 last_warning = jiffies;
1697 }
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001698 while (ret == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001699 yield();
1700 ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS);
1701 }
1702 }
1703 return ret;
1704}
1705
1706static void journal_free_journal_head(struct journal_head *jh)
1707{
1708#ifdef CONFIG_JBD_DEBUG
1709 atomic_dec(&nr_journal_heads);
Randy Dunlapc9cf5522006-06-27 02:53:52 -07001710 memset(jh, JBD_POISON_FREE, sizeof(*jh));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001711#endif
1712 kmem_cache_free(journal_head_cache, jh);
1713}
1714
1715/*
1716 * A journal_head is attached to a buffer_head whenever JBD has an
1717 * interest in the buffer.
1718 *
1719 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
1720 * is set. This bit is tested in core kernel code where we need to take
1721 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
1722 * there.
1723 *
1724 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
1725 *
1726 * When a buffer has its BH_JBD bit set it is immune from being released by
1727 * core kernel code, mainly via ->b_count.
1728 *
1729 * A journal_head may be detached from its buffer_head when the journal_head's
1730 * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL.
1731 * Various places in JBD call journal_remove_journal_head() to indicate that the
1732 * journal_head can be dropped if needed.
1733 *
1734 * Various places in the kernel want to attach a journal_head to a buffer_head
1735 * _before_ attaching the journal_head to a transaction. To protect the
1736 * journal_head in this situation, journal_add_journal_head elevates the
1737 * journal_head's b_jcount refcount by one. The caller must call
1738 * journal_put_journal_head() to undo this.
1739 *
1740 * So the typical usage would be:
1741 *
1742 * (Attach a journal_head if needed. Increments b_jcount)
1743 * struct journal_head *jh = journal_add_journal_head(bh);
1744 * ...
1745 * jh->b_transaction = xxx;
1746 * journal_put_journal_head(jh);
1747 *
1748 * Now, the journal_head's b_jcount is zero, but it is safe from being released
1749 * because it has a non-zero b_transaction.
1750 */
1751
1752/*
1753 * Give a buffer_head a journal_head.
1754 *
1755 * Doesn't need the journal lock.
1756 * May sleep.
1757 */
1758struct journal_head *journal_add_journal_head(struct buffer_head *bh)
1759{
1760 struct journal_head *jh;
1761 struct journal_head *new_jh = NULL;
1762
1763repeat:
1764 if (!buffer_jbd(bh)) {
1765 new_jh = journal_alloc_journal_head();
1766 memset(new_jh, 0, sizeof(*new_jh));
1767 }
1768
1769 jbd_lock_bh_journal_head(bh);
1770 if (buffer_jbd(bh)) {
1771 jh = bh2jh(bh);
1772 } else {
1773 J_ASSERT_BH(bh,
1774 (atomic_read(&bh->b_count) > 0) ||
1775 (bh->b_page && bh->b_page->mapping));
1776
1777 if (!new_jh) {
1778 jbd_unlock_bh_journal_head(bh);
1779 goto repeat;
1780 }
1781
1782 jh = new_jh;
1783 new_jh = NULL; /* We consumed it */
1784 set_buffer_jbd(bh);
1785 bh->b_private = jh;
1786 jh->b_bh = bh;
1787 get_bh(bh);
1788 BUFFER_TRACE(bh, "added journal_head");
1789 }
1790 jh->b_jcount++;
1791 jbd_unlock_bh_journal_head(bh);
1792 if (new_jh)
1793 journal_free_journal_head(new_jh);
1794 return bh->b_private;
1795}
1796
1797/*
1798 * Grab a ref against this buffer_head's journal_head. If it ended up not
1799 * having a journal_head, return NULL
1800 */
1801struct journal_head *journal_grab_journal_head(struct buffer_head *bh)
1802{
1803 struct journal_head *jh = NULL;
1804
1805 jbd_lock_bh_journal_head(bh);
1806 if (buffer_jbd(bh)) {
1807 jh = bh2jh(bh);
1808 jh->b_jcount++;
1809 }
1810 jbd_unlock_bh_journal_head(bh);
1811 return jh;
1812}
1813
1814static void __journal_remove_journal_head(struct buffer_head *bh)
1815{
1816 struct journal_head *jh = bh2jh(bh);
1817
1818 J_ASSERT_JH(jh, jh->b_jcount >= 0);
1819
1820 get_bh(bh);
1821 if (jh->b_jcount == 0) {
1822 if (jh->b_transaction == NULL &&
1823 jh->b_next_transaction == NULL &&
1824 jh->b_cp_transaction == NULL) {
1825 J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
1826 J_ASSERT_BH(bh, buffer_jbd(bh));
1827 J_ASSERT_BH(bh, jh2bh(jh) == bh);
1828 BUFFER_TRACE(bh, "remove journal_head");
1829 if (jh->b_frozen_data) {
1830 printk(KERN_WARNING "%s: freeing "
1831 "b_frozen_data\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -07001832 __func__);
Mingming Caoc089d492007-10-16 18:38:25 -04001833 jbd_free(jh->b_frozen_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834 }
1835 if (jh->b_committed_data) {
1836 printk(KERN_WARNING "%s: freeing "
1837 "b_committed_data\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -07001838 __func__);
Mingming Caoc089d492007-10-16 18:38:25 -04001839 jbd_free(jh->b_committed_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001840 }
1841 bh->b_private = NULL;
1842 jh->b_bh = NULL; /* debug, really */
1843 clear_buffer_jbd(bh);
1844 __brelse(bh);
1845 journal_free_journal_head(jh);
1846 } else {
1847 BUFFER_TRACE(bh, "journal_head was locked");
1848 }
1849 }
1850}
1851
1852/*
1853 * journal_remove_journal_head(): if the buffer isn't attached to a transaction
1854 * and has a zero b_jcount then remove and release its journal_head. If we did
1855 * see that the buffer is not used by any transaction we also "logically"
1856 * decrement ->b_count.
1857 *
1858 * We in fact take an additional increment on ->b_count as a convenience,
1859 * because the caller usually wants to do additional things with the bh
1860 * after calling here.
1861 * The caller of journal_remove_journal_head() *must* run __brelse(bh) at some
1862 * time. Once the caller has run __brelse(), the buffer is eligible for
1863 * reaping by try_to_free_buffers().
1864 */
1865void journal_remove_journal_head(struct buffer_head *bh)
1866{
1867 jbd_lock_bh_journal_head(bh);
1868 __journal_remove_journal_head(bh);
1869 jbd_unlock_bh_journal_head(bh);
1870}
1871
1872/*
1873 * Drop a reference on the passed journal_head. If it fell to zero then try to
1874 * release the journal_head from the buffer_head.
1875 */
1876void journal_put_journal_head(struct journal_head *jh)
1877{
1878 struct buffer_head *bh = jh2bh(jh);
1879
1880 jbd_lock_bh_journal_head(bh);
1881 J_ASSERT_JH(jh, jh->b_jcount > 0);
1882 --jh->b_jcount;
1883 if (!jh->b_jcount && !jh->b_transaction) {
1884 __journal_remove_journal_head(bh);
1885 __brelse(bh);
1886 }
1887 jbd_unlock_bh_journal_head(bh);
1888}
1889
1890/*
Jose R. Santosc2a91592007-10-18 23:39:22 -07001891 * debugfs tunables
Linus Torvalds1da177e2005-04-16 15:20:36 -07001892 */
Jose R. Santosc2a91592007-10-18 23:39:22 -07001893#ifdef CONFIG_JBD_DEBUG
1894
1895u8 journal_enable_debug __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001896EXPORT_SYMBOL(journal_enable_debug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897
Jose R. Santosc2a91592007-10-18 23:39:22 -07001898static struct dentry *jbd_debugfs_dir;
1899static struct dentry *jbd_debug;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001900
Jose R. Santosc2a91592007-10-18 23:39:22 -07001901static void __init jbd_create_debugfs_entry(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902{
Jose R. Santosc2a91592007-10-18 23:39:22 -07001903 jbd_debugfs_dir = debugfs_create_dir("jbd", NULL);
1904 if (jbd_debugfs_dir)
1905 jbd_debug = debugfs_create_u8("jbd-debug", S_IRUGO,
1906 jbd_debugfs_dir,
1907 &journal_enable_debug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908}
1909
Jose R. Santosc2a91592007-10-18 23:39:22 -07001910static void __exit jbd_remove_debugfs_entry(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911{
Jose R. Santosc2a91592007-10-18 23:39:22 -07001912 debugfs_remove(jbd_debug);
1913 debugfs_remove(jbd_debugfs_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914}
1915
1916#else
1917
Jose R. Santosc2a91592007-10-18 23:39:22 -07001918static inline void jbd_create_debugfs_entry(void)
1919{
1920}
1921
1922static inline void jbd_remove_debugfs_entry(void)
1923{
1924}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001925
1926#endif
1927
Christoph Lametere18b8902006-12-06 20:33:20 -08001928struct kmem_cache *jbd_handle_cache;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001929
1930static int __init journal_init_handle_cache(void)
1931{
1932 jbd_handle_cache = kmem_cache_create("journal_handle",
1933 sizeof(handle_t),
1934 0, /* offset */
Mel Gormane12ba742007-10-16 01:25:52 -07001935 SLAB_TEMPORARY, /* flags */
Paul Mundt20c2df82007-07-20 10:11:58 +09001936 NULL); /* ctor */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937 if (jbd_handle_cache == NULL) {
1938 printk(KERN_EMERG "JBD: failed to create handle cache\n");
1939 return -ENOMEM;
1940 }
1941 return 0;
1942}
1943
1944static void journal_destroy_handle_cache(void)
1945{
1946 if (jbd_handle_cache)
1947 kmem_cache_destroy(jbd_handle_cache);
1948}
1949
1950/*
1951 * Module startup and shutdown
1952 */
1953
1954static int __init journal_init_caches(void)
1955{
1956 int ret;
1957
1958 ret = journal_init_revoke_caches();
1959 if (ret == 0)
1960 ret = journal_init_journal_head_cache();
1961 if (ret == 0)
1962 ret = journal_init_handle_cache();
1963 return ret;
1964}
1965
1966static void journal_destroy_caches(void)
1967{
1968 journal_destroy_revoke_caches();
1969 journal_destroy_journal_head_cache();
1970 journal_destroy_handle_cache();
1971}
1972
1973static int __init journal_init(void)
1974{
1975 int ret;
1976
Alexey Dobriyan2aed3482006-09-27 01:49:28 -07001977 BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
Adrian Bunk022a4a72005-09-06 15:16:41 -07001978
Linus Torvalds1da177e2005-04-16 15:20:36 -07001979 ret = journal_init_caches();
1980 if (ret != 0)
1981 journal_destroy_caches();
Jose R. Santosc2a91592007-10-18 23:39:22 -07001982 jbd_create_debugfs_entry();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001983 return ret;
1984}
1985
1986static void __exit journal_exit(void)
1987{
1988#ifdef CONFIG_JBD_DEBUG
1989 int n = atomic_read(&nr_journal_heads);
1990 if (n)
1991 printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n);
1992#endif
Jose R. Santosc2a91592007-10-18 23:39:22 -07001993 jbd_remove_debugfs_entry();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994 journal_destroy_caches();
1995}
1996
1997MODULE_LICENSE("GPL");
1998module_init(journal_init);
1999module_exit(journal_exit);
2000