blob: b99c3b3654c49ee33f86bc8883319a55f11a9711 [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_update_superblock);
72EXPORT_SYMBOL(journal_abort);
73EXPORT_SYMBOL(journal_errno);
74EXPORT_SYMBOL(journal_ack_err);
75EXPORT_SYMBOL(journal_clear_err);
76EXPORT_SYMBOL(log_wait_commit);
77EXPORT_SYMBOL(journal_start_commit);
78EXPORT_SYMBOL(journal_force_commit_nested);
79EXPORT_SYMBOL(journal_wipe);
80EXPORT_SYMBOL(journal_blocks_per_page);
81EXPORT_SYMBOL(journal_invalidatepage);
82EXPORT_SYMBOL(journal_try_to_free_buffers);
83EXPORT_SYMBOL(journal_force_commit);
84
85static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
Adrian Bunk022a4a72005-09-06 15:16:41 -070086static void __journal_abort_soft (journal_t *journal, int errno);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
88/*
89 * Helper function used to manage commit timeouts
90 */
91
92static void commit_timeout(unsigned long __data)
93{
94 struct task_struct * p = (struct task_struct *) __data;
95
96 wake_up_process(p);
97}
98
Linus Torvalds1da177e2005-04-16 15:20:36 -070099/*
100 * kjournald: The main thread function used to manage a logging device
101 * journal.
102 *
103 * This kernel thread is responsible for two things:
104 *
105 * 1) COMMIT: Every so often we need to commit the current state of the
106 * filesystem to disk. The journal thread is responsible for writing
107 * all of the metadata buffers to disk.
108 *
109 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
110 * of the data in that part of the log has been rewritten elsewhere on
111 * the disk. Flushing these old buffers to reclaim space in the log is
112 * known as checkpointing, and this thread is responsible for that job.
113 */
114
Adrian Bunk022a4a72005-09-06 15:16:41 -0700115static int kjournald(void *arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116{
Andrew Mortone3df1892006-03-25 03:06:53 -0800117 journal_t *journal = arg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 transaction_t *transaction;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119
Andrew Mortone3df1892006-03-25 03:06:53 -0800120 /*
121 * Set up an interval timer which can be used to trigger a commit wakeup
122 * after the commit interval expires
123 */
124 setup_timer(&journal->j_commit_timer, commit_timeout,
125 (unsigned long)current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126
127 /* Record that the journal thread is running */
128 journal->j_task = current;
129 wake_up(&journal->j_wait_done_commit);
130
131 printk(KERN_INFO "kjournald starting. Commit interval %ld seconds\n",
132 journal->j_commit_interval / HZ);
133
134 /*
135 * And now, wait forever for commit wakeup events.
136 */
137 spin_lock(&journal->j_state_lock);
138
139loop:
140 if (journal->j_flags & JFS_UNMOUNT)
141 goto end_loop;
142
143 jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
144 journal->j_commit_sequence, journal->j_commit_request);
145
146 if (journal->j_commit_sequence != journal->j_commit_request) {
147 jbd_debug(1, "OK, requests differ\n");
148 spin_unlock(&journal->j_state_lock);
Andrew Mortone3df1892006-03-25 03:06:53 -0800149 del_timer_sync(&journal->j_commit_timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 journal_commit_transaction(journal);
151 spin_lock(&journal->j_state_lock);
152 goto loop;
153 }
154
155 wake_up(&journal->j_wait_done_commit);
Christoph Lameter3e1d1d22005-06-24 23:13:50 -0700156 if (freezing(current)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 /*
158 * The simpler the better. Flushing journal isn't a
159 * good idea, because that depends on threads that may
160 * be already stopped.
161 */
162 jbd_debug(1, "Now suspending kjournald\n");
163 spin_unlock(&journal->j_state_lock);
Christoph Lameter3e1d1d22005-06-24 23:13:50 -0700164 refrigerator();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 spin_lock(&journal->j_state_lock);
166 } else {
167 /*
168 * We assume on resume that commits are already there,
169 * so we don't sleep
170 */
171 DEFINE_WAIT(wait);
172 int should_sleep = 1;
173
174 prepare_to_wait(&journal->j_wait_commit, &wait,
175 TASK_INTERRUPTIBLE);
176 if (journal->j_commit_sequence != journal->j_commit_request)
177 should_sleep = 0;
178 transaction = journal->j_running_transaction;
179 if (transaction && time_after_eq(jiffies,
180 transaction->t_expires))
181 should_sleep = 0;
Mark Fashehcbf0d272005-09-06 15:19:08 -0700182 if (journal->j_flags & JFS_UNMOUNT)
Dave Kleikampe9ad5622006-09-27 01:49:35 -0700183 should_sleep = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 if (should_sleep) {
185 spin_unlock(&journal->j_state_lock);
186 schedule();
187 spin_lock(&journal->j_state_lock);
188 }
189 finish_wait(&journal->j_wait_commit, &wait);
190 }
191
192 jbd_debug(1, "kjournald wakes\n");
193
194 /*
195 * Were we woken up by a commit wakeup event?
196 */
197 transaction = journal->j_running_transaction;
198 if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
199 journal->j_commit_request = transaction->t_tid;
200 jbd_debug(1, "woke because of timeout\n");
201 }
202 goto loop;
203
204end_loop:
205 spin_unlock(&journal->j_state_lock);
Andrew Mortone3df1892006-03-25 03:06:53 -0800206 del_timer_sync(&journal->j_commit_timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 journal->j_task = NULL;
208 wake_up(&journal->j_wait_done_commit);
209 jbd_debug(1, "Journal thread exiting.\n");
210 return 0;
211}
212
Pavel Emelianov97f06782007-05-08 00:30:42 -0700213static int journal_start_thread(journal_t *journal)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214{
Pavel Emelianov97f06782007-05-08 00:30:42 -0700215 struct task_struct *t;
216
217 t = kthread_run(kjournald, journal, "kjournald");
218 if (IS_ERR(t))
219 return PTR_ERR(t);
220
Stephen Hemmingerc80544d2007-10-18 03:07:05 -0700221 wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
Pavel Emelianov97f06782007-05-08 00:30:42 -0700222 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223}
224
225static void journal_kill_thread(journal_t *journal)
226{
227 spin_lock(&journal->j_state_lock);
228 journal->j_flags |= JFS_UNMOUNT;
229
230 while (journal->j_task) {
231 wake_up(&journal->j_wait_commit);
232 spin_unlock(&journal->j_state_lock);
Stephen Hemmingerc80544d2007-10-18 03:07:05 -0700233 wait_event(journal->j_wait_done_commit,
234 journal->j_task == NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 spin_lock(&journal->j_state_lock);
236 }
237 spin_unlock(&journal->j_state_lock);
238}
239
240/*
241 * journal_write_metadata_buffer: write a metadata buffer to the journal.
242 *
243 * Writes a metadata buffer to a given disk block. The actual IO is not
244 * performed but a new buffer_head is constructed which labels the data
245 * to be written with the correct destination disk block.
246 *
247 * Any magic-number escaping which needs to be done will cause a
248 * copy-out here. If the buffer happens to start with the
249 * JFS_MAGIC_NUMBER, then we can't write it to the log directly: the
250 * magic number is only written to the log for descripter blocks. In
251 * this case, we copy the data and replace the first word with 0, and we
252 * return a result code which indicates that this buffer needs to be
253 * marked as an escaped buffer in the corresponding log descriptor
254 * block. The missing word can then be restored when the block is read
255 * during recovery.
256 *
257 * If the source buffer has already been modified by a new transaction
258 * since we took the last commit snapshot, we use the frozen copy of
259 * that data for IO. If we end up using the existing buffer_head's data
260 * for the write, then we *have* to lock the buffer to prevent anyone
261 * else from using and possibly modifying it while the IO is in
262 * progress.
263 *
264 * The function returns a pointer to the buffer_heads to be used for IO.
265 *
266 * We assume that the journal has already been locked in this function.
267 *
268 * Return value:
269 * <0: Error
270 * >=0: Finished OK
271 *
272 * On success:
273 * Bit 0 set == escape performed on the data
274 * Bit 1 set == buffer copy-out performed (kfree the data after IO)
275 */
276
277int journal_write_metadata_buffer(transaction_t *transaction,
278 struct journal_head *jh_in,
279 struct journal_head **jh_out,
Eric Sandeen37ed3222006-09-27 01:49:31 -0700280 unsigned long blocknr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281{
282 int need_copy_out = 0;
283 int done_copy_out = 0;
284 int do_escape = 0;
285 char *mapped_data;
286 struct buffer_head *new_bh;
287 struct journal_head *new_jh;
288 struct page *new_page;
289 unsigned int new_offset;
290 struct buffer_head *bh_in = jh2bh(jh_in);
291
292 /*
293 * The buffer really shouldn't be locked: only the current committing
294 * transaction is allowed to write it, so nobody else is allowed
295 * to do any IO.
296 *
297 * akpm: except if we're journalling data, and write() output is
298 * also part of a shared mapping, and another thread has
299 * decided to launch a writepage() against this buffer.
300 */
301 J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
302
303 new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
304
305 /*
306 * If a new transaction has already done a buffer copy-out, then
307 * we use that version of the data for the commit.
308 */
309 jbd_lock_bh_state(bh_in);
310repeat:
311 if (jh_in->b_frozen_data) {
312 done_copy_out = 1;
313 new_page = virt_to_page(jh_in->b_frozen_data);
314 new_offset = offset_in_page(jh_in->b_frozen_data);
315 } else {
316 new_page = jh2bh(jh_in)->b_page;
317 new_offset = offset_in_page(jh2bh(jh_in)->b_data);
318 }
319
320 mapped_data = kmap_atomic(new_page, KM_USER0);
321 /*
322 * Check for escaping
323 */
324 if (*((__be32 *)(mapped_data + new_offset)) ==
325 cpu_to_be32(JFS_MAGIC_NUMBER)) {
326 need_copy_out = 1;
327 do_escape = 1;
328 }
329 kunmap_atomic(mapped_data, KM_USER0);
330
331 /*
332 * Do we need to do a data copy?
333 */
334 if (need_copy_out && !done_copy_out) {
335 char *tmp;
336
337 jbd_unlock_bh_state(bh_in);
Mingming Caoc089d492007-10-16 18:38:25 -0400338 tmp = jbd_alloc(bh_in->b_size, GFP_NOFS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 jbd_lock_bh_state(bh_in);
340 if (jh_in->b_frozen_data) {
Mingming Caoc089d492007-10-16 18:38:25 -0400341 jbd_free(tmp, bh_in->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 goto repeat;
343 }
344
345 jh_in->b_frozen_data = tmp;
346 mapped_data = kmap_atomic(new_page, KM_USER0);
347 memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size);
348 kunmap_atomic(mapped_data, KM_USER0);
349
350 new_page = virt_to_page(tmp);
351 new_offset = offset_in_page(tmp);
352 done_copy_out = 1;
353 }
354
355 /*
356 * Did we need to do an escaping? Now we've done all the
357 * copying, we can finally do so.
358 */
359 if (do_escape) {
360 mapped_data = kmap_atomic(new_page, KM_USER0);
361 *((unsigned int *)(mapped_data + new_offset)) = 0;
362 kunmap_atomic(mapped_data, KM_USER0);
363 }
364
365 /* keep subsequent assertions sane */
366 new_bh->b_state = 0;
367 init_buffer(new_bh, NULL, NULL);
368 atomic_set(&new_bh->b_count, 1);
369 jbd_unlock_bh_state(bh_in);
370
371 new_jh = journal_add_journal_head(new_bh); /* This sleeps */
372
373 set_bh_page(new_bh, new_page, new_offset);
374 new_jh->b_transaction = NULL;
375 new_bh->b_size = jh2bh(jh_in)->b_size;
376 new_bh->b_bdev = transaction->t_journal->j_dev;
377 new_bh->b_blocknr = blocknr;
378 set_buffer_mapped(new_bh);
379 set_buffer_dirty(new_bh);
380
381 *jh_out = new_jh;
382
383 /*
384 * The to-be-written buffer needs to get moved to the io queue,
385 * and the original buffer whose contents we are shadowing or
386 * copying is moved to the transaction's shadow queue.
387 */
388 JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
389 journal_file_buffer(jh_in, transaction, BJ_Shadow);
390 JBUFFER_TRACE(new_jh, "file as BJ_IO");
391 journal_file_buffer(new_jh, transaction, BJ_IO);
392
393 return do_escape | (done_copy_out << 1);
394}
395
396/*
397 * Allocation code for the journal file. Manage the space left in the
398 * journal, so that we can begin checkpointing when appropriate.
399 */
400
401/*
402 * __log_space_left: Return the number of free blocks left in the journal.
403 *
404 * Called with the journal already locked.
405 *
406 * Called under j_state_lock
407 */
408
409int __log_space_left(journal_t *journal)
410{
411 int left = journal->j_free;
412
413 assert_spin_locked(&journal->j_state_lock);
414
415 /*
416 * Be pessimistic here about the number of those free blocks which
417 * might be required for log descriptor control blocks.
418 */
419
420#define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */
421
422 left -= MIN_LOG_RESERVED_BLOCKS;
423
424 if (left <= 0)
425 return 0;
426 left -= (left >> 3);
427 return left;
428}
429
430/*
431 * Called under j_state_lock. Returns true if a transaction was started.
432 */
433int __log_start_commit(journal_t *journal, tid_t target)
434{
435 /*
436 * Are we already doing a recent enough commit?
437 */
438 if (!tid_geq(journal->j_commit_request, target)) {
439 /*
440 * We want a new commit: OK, mark the request and wakup the
441 * commit thread. We do _not_ do the commit ourselves.
442 */
443
444 journal->j_commit_request = target;
445 jbd_debug(1, "JBD: requesting commit %d/%d\n",
446 journal->j_commit_request,
447 journal->j_commit_sequence);
448 wake_up(&journal->j_wait_commit);
449 return 1;
450 }
451 return 0;
452}
453
454int log_start_commit(journal_t *journal, tid_t tid)
455{
456 int ret;
457
458 spin_lock(&journal->j_state_lock);
459 ret = __log_start_commit(journal, tid);
460 spin_unlock(&journal->j_state_lock);
461 return ret;
462}
463
464/*
465 * Force and wait upon a commit if the calling process is not within
466 * transaction. This is used for forcing out undo-protected data which contains
467 * bitmaps, when the fs is running out of space.
468 *
469 * We can only force the running transaction if we don't have an active handle;
470 * otherwise, we will deadlock.
471 *
472 * Returns true if a transaction was started.
473 */
474int journal_force_commit_nested(journal_t *journal)
475{
476 transaction_t *transaction = NULL;
477 tid_t tid;
478
479 spin_lock(&journal->j_state_lock);
480 if (journal->j_running_transaction && !current->journal_info) {
481 transaction = journal->j_running_transaction;
482 __log_start_commit(journal, transaction->t_tid);
483 } else if (journal->j_committing_transaction)
484 transaction = journal->j_committing_transaction;
485
486 if (!transaction) {
487 spin_unlock(&journal->j_state_lock);
488 return 0; /* Nothing to retry */
489 }
490
491 tid = transaction->t_tid;
492 spin_unlock(&journal->j_state_lock);
493 log_wait_commit(journal, tid);
494 return 1;
495}
496
497/*
498 * Start a commit of the current running transaction (if any). Returns true
499 * if a transaction was started, and fills its tid in at *ptid
500 */
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
509 ret = __log_start_commit(journal, tid);
510 if (ret && ptid)
511 *ptid = tid;
512 } else if (journal->j_committing_transaction && ptid) {
513 /*
514 * If ext3_write_super() recently started a commit, then we
515 * have to wait for completion of that transaction
516 */
517 *ptid = journal->j_committing_transaction->t_tid;
518 ret = 1;
519 }
520 spin_unlock(&journal->j_state_lock);
521 return ret;
522}
523
524/*
525 * Wait for a specified commit to complete.
526 * The caller may not hold the journal lock.
527 */
528int log_wait_commit(journal_t *journal, tid_t tid)
529{
530 int err = 0;
531
532#ifdef CONFIG_JBD_DEBUG
533 spin_lock(&journal->j_state_lock);
534 if (!tid_geq(journal->j_commit_request, tid)) {
535 printk(KERN_EMERG
536 "%s: error: j_commit_request=%d, tid=%d\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700537 __func__, journal->j_commit_request, tid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 }
539 spin_unlock(&journal->j_state_lock);
540#endif
541 spin_lock(&journal->j_state_lock);
542 while (tid_gt(tid, journal->j_commit_sequence)) {
543 jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n",
544 tid, journal->j_commit_sequence);
545 wake_up(&journal->j_wait_commit);
546 spin_unlock(&journal->j_state_lock);
547 wait_event(journal->j_wait_done_commit,
548 !tid_gt(tid, journal->j_commit_sequence));
549 spin_lock(&journal->j_state_lock);
550 }
551 spin_unlock(&journal->j_state_lock);
552
553 if (unlikely(is_journal_aborted(journal))) {
554 printk(KERN_EMERG "journal commit I/O error\n");
555 err = -EIO;
556 }
557 return err;
558}
559
560/*
561 * Log buffer allocation routines:
562 */
563
564int journal_next_log_block(journal_t *journal, unsigned long *retp)
565{
566 unsigned long blocknr;
567
568 spin_lock(&journal->j_state_lock);
569 J_ASSERT(journal->j_free > 1);
570
571 blocknr = journal->j_head;
572 journal->j_head++;
573 journal->j_free--;
574 if (journal->j_head == journal->j_last)
575 journal->j_head = journal->j_first;
576 spin_unlock(&journal->j_state_lock);
577 return journal_bmap(journal, blocknr, retp);
578}
579
580/*
581 * Conversion of logical to physical block numbers for the journal
582 *
583 * On external journals the journal blocks are identity-mapped, so
584 * this is a no-op. If needed, we can use j_blk_offset - everything is
585 * ready.
586 */
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700587int journal_bmap(journal_t *journal, unsigned long blocknr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 unsigned long *retp)
589{
590 int err = 0;
591 unsigned long ret;
592
593 if (journal->j_inode) {
594 ret = bmap(journal->j_inode, blocknr);
595 if (ret)
596 *retp = ret;
597 else {
598 char b[BDEVNAME_SIZE];
599
600 printk(KERN_ALERT "%s: journal block not found "
601 "at offset %lu on %s\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700602 __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 blocknr,
604 bdevname(journal->j_dev, b));
605 err = -EIO;
606 __journal_abort_soft(journal, err);
607 }
608 } else {
609 *retp = blocknr; /* +journal->j_blk_offset */
610 }
611 return err;
612}
613
614/*
615 * We play buffer_head aliasing tricks to write data/metadata blocks to
616 * the journal without copying their contents, but for journal
617 * descriptor blocks we do need to generate bona fide buffers.
618 *
619 * After the caller of journal_get_descriptor_buffer() has finished modifying
620 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
621 * But we don't bother doing that, so there will be coherency problems with
622 * mmaps of blockdevs which hold live JBD-controlled filesystems.
623 */
624struct journal_head *journal_get_descriptor_buffer(journal_t *journal)
625{
626 struct buffer_head *bh;
627 unsigned long blocknr;
628 int err;
629
630 err = journal_next_log_block(journal, &blocknr);
631
632 if (err)
633 return NULL;
634
635 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
636 lock_buffer(bh);
637 memset(bh->b_data, 0, journal->j_blocksize);
638 set_buffer_uptodate(bh);
639 unlock_buffer(bh);
640 BUFFER_TRACE(bh, "return this buffer");
641 return journal_add_journal_head(bh);
642}
643
644/*
645 * Management for journal control blocks: functions to create and
646 * destroy journal_t structures, and to initialise and read existing
647 * journal blocks from disk. */
648
649/* First: create and setup a journal_t object in memory. We initialise
650 * very few fields yet: that has to wait until we have created the
651 * journal structures from from scratch, or loaded them from disk. */
652
653static journal_t * journal_init_common (void)
654{
655 journal_t *journal;
656 int err;
657
Mingming Cao8c3478a2007-10-18 23:39:20 -0700658 journal = kzalloc(sizeof(*journal), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 if (!journal)
660 goto fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661
662 init_waitqueue_head(&journal->j_wait_transaction_locked);
663 init_waitqueue_head(&journal->j_wait_logspace);
664 init_waitqueue_head(&journal->j_wait_done_commit);
665 init_waitqueue_head(&journal->j_wait_checkpoint);
666 init_waitqueue_head(&journal->j_wait_commit);
667 init_waitqueue_head(&journal->j_wait_updates);
Arjan van de Ven2c68ee72006-03-23 03:00:35 -0800668 mutex_init(&journal->j_barrier);
669 mutex_init(&journal->j_checkpoint_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 spin_lock_init(&journal->j_revoke_lock);
671 spin_lock_init(&journal->j_list_lock);
672 spin_lock_init(&journal->j_state_lock);
673
674 journal->j_commit_interval = (HZ * JBD_DEFAULT_MAX_COMMIT_AGE);
675
676 /* The journal is marked for error until we succeed with recovery! */
677 journal->j_flags = JFS_ABORT;
678
679 /* Set up a default-sized revoke table for the new mount. */
680 err = journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
681 if (err) {
682 kfree(journal);
683 goto fail;
684 }
685 return journal;
686fail:
687 return NULL;
688}
689
690/* journal_init_dev and journal_init_inode:
691 *
692 * Create a journal structure assigned some fixed set of disk blocks to
693 * the journal. We don't actually touch those disk blocks yet, but we
694 * need to set up all of the mapping information to tell the journaling
695 * system where the journal blocks are.
696 *
697 */
698
699/**
Randy Dunlap0cf01f62008-03-19 17:00:44 -0700700 * journal_t * journal_init_dev() - creates and initialises a journal structure
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 * @bdev: Block device on which to create the journal
702 * @fs_dev: Device which hold journalled filesystem for this journal.
703 * @start: Block nr Start of journal.
Eric Sandeen37ed3222006-09-27 01:49:31 -0700704 * @len: Length of the journal in blocks.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 * @blocksize: blocksize of journalling device
Randy Dunlap0cf01f62008-03-19 17:00:44 -0700706 *
707 * Returns: a newly created journal_t *
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700708 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 * journal_init_dev creates a journal which maps a fixed contiguous
710 * range of blocks on an arbitrary block device.
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700711 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 */
713journal_t * journal_init_dev(struct block_device *bdev,
714 struct block_device *fs_dev,
715 int start, int len, int blocksize)
716{
717 journal_t *journal = journal_init_common();
718 struct buffer_head *bh;
719 int n;
720
721 if (!journal)
722 return NULL;
723
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 /* journal descriptor can store up to n blocks -bzzz */
Zoltan Menyhartd1807792006-09-29 01:58:40 -0700725 journal->j_blocksize = blocksize;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 n = journal->j_blocksize / sizeof(journal_block_tag_t);
727 journal->j_wbufsize = n;
728 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
729 if (!journal->j_wbuf) {
730 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700731 __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 kfree(journal);
733 journal = NULL;
Eric Sesterhenn41716c72006-10-11 01:20:37 -0700734 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 }
Zoltan Menyhartd1807792006-09-29 01:58:40 -0700736 journal->j_dev = bdev;
737 journal->j_fs_dev = fs_dev;
738 journal->j_blk_offset = start;
739 journal->j_maxlen = len;
740
741 bh = __getblk(journal->j_dev, start, journal->j_blocksize);
742 J_ASSERT(bh != NULL);
743 journal->j_sb_buffer = bh;
744 journal->j_superblock = (journal_superblock_t *)bh->b_data;
Eric Sesterhenn41716c72006-10-11 01:20:37 -0700745out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 return journal;
747}
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700748
749/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 * journal_t * journal_init_inode () - creates a journal which maps to a inode.
751 * @inode: An inode to create the journal in
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700752 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 * journal_init_inode creates a journal which maps an on-disk inode as
754 * the journal. The inode must exist already, must support bmap() and
755 * must have all data blocks preallocated.
756 */
757journal_t * journal_init_inode (struct inode *inode)
758{
759 struct buffer_head *bh;
760 journal_t *journal = journal_init_common();
761 int err;
762 int n;
763 unsigned long blocknr;
764
765 if (!journal)
766 return NULL;
767
768 journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
769 journal->j_inode = inode;
770 jbd_debug(1,
771 "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700772 journal, inode->i_sb->s_id, inode->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773 (long long) inode->i_size,
774 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
775
776 journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
777 journal->j_blocksize = inode->i_sb->s_blocksize;
778
779 /* journal descriptor can store up to n blocks -bzzz */
780 n = journal->j_blocksize / sizeof(journal_block_tag_t);
781 journal->j_wbufsize = n;
782 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
783 if (!journal->j_wbuf) {
784 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700785 __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 kfree(journal);
787 return NULL;
788 }
789
790 err = journal_bmap(journal, 0, &blocknr);
791 /* If that failed, give up */
792 if (err) {
793 printk(KERN_ERR "%s: Cannnot locate journal superblock\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700794 __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 kfree(journal);
796 return NULL;
797 }
798
799 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
800 J_ASSERT(bh != NULL);
801 journal->j_sb_buffer = bh;
802 journal->j_superblock = (journal_superblock_t *)bh->b_data;
803
804 return journal;
805}
806
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700807/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 * If the journal init or create aborts, we need to mark the journal
809 * superblock as being NULL to prevent the journal destroy from writing
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700810 * back a bogus superblock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 */
812static void journal_fail_superblock (journal_t *journal)
813{
814 struct buffer_head *bh = journal->j_sb_buffer;
815 brelse(bh);
816 journal->j_sb_buffer = NULL;
817}
818
819/*
820 * Given a journal_t structure, initialise the various fields for
821 * startup of a new journaling session. We use this both when creating
822 * a journal, and after recovering an old journal to reset it for
823 * subsequent use.
824 */
825
826static int journal_reset(journal_t *journal)
827{
828 journal_superblock_t *sb = journal->j_superblock;
Eric Sandeen37ed3222006-09-27 01:49:31 -0700829 unsigned long first, last;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830
831 first = be32_to_cpu(sb->s_first);
832 last = be32_to_cpu(sb->s_maxlen);
833
834 journal->j_first = first;
835 journal->j_last = last;
836
837 journal->j_head = first;
838 journal->j_tail = first;
839 journal->j_free = last - first;
840
841 journal->j_tail_sequence = journal->j_transaction_sequence;
842 journal->j_commit_sequence = journal->j_transaction_sequence - 1;
843 journal->j_commit_request = journal->j_commit_sequence;
844
845 journal->j_max_transaction_buffers = journal->j_maxlen / 4;
846
847 /* Add the dynamic fields and write it to disk. */
848 journal_update_superblock(journal, 1);
Pavel Emelianov97f06782007-05-08 00:30:42 -0700849 return journal_start_thread(journal);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850}
851
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700852/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853 * int journal_create() - Initialise the new journal file
854 * @journal: Journal to create. This structure must have been initialised
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700855 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 * Given a journal_t structure which tells us which disk blocks we can
857 * use, create a new journal superblock and initialise all of the
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700858 * journal fields from scratch.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 **/
860int journal_create(journal_t *journal)
861{
862 unsigned long blocknr;
863 struct buffer_head *bh;
864 journal_superblock_t *sb;
865 int i, err;
866
867 if (journal->j_maxlen < JFS_MIN_JOURNAL_BLOCKS) {
868 printk (KERN_ERR "Journal length (%d blocks) too short.\n",
869 journal->j_maxlen);
870 journal_fail_superblock(journal);
871 return -EINVAL;
872 }
873
874 if (journal->j_inode == NULL) {
875 /*
876 * We don't know what block to start at!
877 */
878 printk(KERN_EMERG
879 "%s: creation of journal on external device!\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700880 __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 BUG();
882 }
883
884 /* Zero out the entire journal on disk. We cannot afford to
885 have any blocks on disk beginning with JFS_MAGIC_NUMBER. */
886 jbd_debug(1, "JBD: Zeroing out journal blocks...\n");
887 for (i = 0; i < journal->j_maxlen; i++) {
888 err = journal_bmap(journal, i, &blocknr);
889 if (err)
890 return err;
891 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
892 lock_buffer(bh);
893 memset (bh->b_data, 0, journal->j_blocksize);
894 BUFFER_TRACE(bh, "marking dirty");
895 mark_buffer_dirty(bh);
896 BUFFER_TRACE(bh, "marking uptodate");
897 set_buffer_uptodate(bh);
898 unlock_buffer(bh);
899 __brelse(bh);
900 }
901
902 sync_blockdev(journal->j_dev);
903 jbd_debug(1, "JBD: journal cleared.\n");
904
905 /* OK, fill in the initial static fields in the new superblock */
906 sb = journal->j_superblock;
907
908 sb->s_header.h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
909 sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2);
910
911 sb->s_blocksize = cpu_to_be32(journal->j_blocksize);
912 sb->s_maxlen = cpu_to_be32(journal->j_maxlen);
913 sb->s_first = cpu_to_be32(1);
914
915 journal->j_transaction_sequence = 1;
916
917 journal->j_flags &= ~JFS_ABORT;
918 journal->j_format_version = 2;
919
920 return journal_reset(journal);
921}
922
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700923/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924 * void journal_update_superblock() - Update journal sb on disk.
925 * @journal: The journal to update.
926 * @wait: Set to '0' if you don't want to wait for IO completion.
927 *
928 * Update a journal's dynamic superblock fields and write it to disk,
929 * optionally waiting for the IO to complete.
930 */
931void journal_update_superblock(journal_t *journal, int wait)
932{
933 journal_superblock_t *sb = journal->j_superblock;
934 struct buffer_head *bh = journal->j_sb_buffer;
935
936 /*
937 * As a special case, if the on-disk copy is already marked as needing
938 * no recovery (s_start == 0) and there are no outstanding transactions
939 * in the filesystem, then we can safely defer the superblock update
940 * until the next commit by setting JFS_FLUSHED. This avoids
941 * attempting a write to a potential-readonly device.
942 */
943 if (sb->s_start == 0 && journal->j_tail_sequence ==
944 journal->j_transaction_sequence) {
945 jbd_debug(1,"JBD: Skipping superblock update on recovered sb "
946 "(start %ld, seq %d, errno %d)\n",
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700947 journal->j_tail, journal->j_tail_sequence,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948 journal->j_errno);
949 goto out;
950 }
951
952 spin_lock(&journal->j_state_lock);
953 jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n",
954 journal->j_tail, journal->j_tail_sequence, journal->j_errno);
955
956 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
957 sb->s_start = cpu_to_be32(journal->j_tail);
958 sb->s_errno = cpu_to_be32(journal->j_errno);
959 spin_unlock(&journal->j_state_lock);
960
961 BUFFER_TRACE(bh, "marking dirty");
962 mark_buffer_dirty(bh);
963 if (wait)
964 sync_dirty_buffer(bh);
965 else
Jan Kara26707692005-09-06 15:19:12 -0700966 ll_rw_block(SWRITE, 1, &bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967
968out:
969 /* If we have just flushed the log (by marking s_start==0), then
970 * any future commit will have to be careful to update the
971 * superblock again to re-record the true start of the log. */
972
973 spin_lock(&journal->j_state_lock);
974 if (sb->s_start)
975 journal->j_flags &= ~JFS_FLUSHED;
976 else
977 journal->j_flags |= JFS_FLUSHED;
978 spin_unlock(&journal->j_state_lock);
979}
980
981/*
982 * Read the superblock for a given journal, performing initial
983 * validation of the format.
984 */
985
986static int journal_get_superblock(journal_t *journal)
987{
988 struct buffer_head *bh;
989 journal_superblock_t *sb;
990 int err = -EIO;
991
992 bh = journal->j_sb_buffer;
993
994 J_ASSERT(bh != NULL);
995 if (!buffer_uptodate(bh)) {
996 ll_rw_block(READ, 1, &bh);
997 wait_on_buffer(bh);
998 if (!buffer_uptodate(bh)) {
999 printk (KERN_ERR
1000 "JBD: IO error reading journal superblock\n");
1001 goto out;
1002 }
1003 }
1004
1005 sb = journal->j_superblock;
1006
1007 err = -EINVAL;
1008
1009 if (sb->s_header.h_magic != cpu_to_be32(JFS_MAGIC_NUMBER) ||
1010 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1011 printk(KERN_WARNING "JBD: no valid journal superblock found\n");
1012 goto out;
1013 }
1014
1015 switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1016 case JFS_SUPERBLOCK_V1:
1017 journal->j_format_version = 1;
1018 break;
1019 case JFS_SUPERBLOCK_V2:
1020 journal->j_format_version = 2;
1021 break;
1022 default:
1023 printk(KERN_WARNING "JBD: unrecognised superblock format ID\n");
1024 goto out;
1025 }
1026
1027 if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
1028 journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
1029 else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
1030 printk (KERN_WARNING "JBD: journal file too short\n");
1031 goto out;
1032 }
1033
1034 return 0;
1035
1036out:
1037 journal_fail_superblock(journal);
1038 return err;
1039}
1040
1041/*
1042 * Load the on-disk journal superblock and read the key fields into the
1043 * journal_t.
1044 */
1045
1046static int load_superblock(journal_t *journal)
1047{
1048 int err;
1049 journal_superblock_t *sb;
1050
1051 err = journal_get_superblock(journal);
1052 if (err)
1053 return err;
1054
1055 sb = journal->j_superblock;
1056
1057 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1058 journal->j_tail = be32_to_cpu(sb->s_start);
1059 journal->j_first = be32_to_cpu(sb->s_first);
1060 journal->j_last = be32_to_cpu(sb->s_maxlen);
1061 journal->j_errno = be32_to_cpu(sb->s_errno);
1062
1063 return 0;
1064}
1065
1066
1067/**
1068 * int journal_load() - Read journal from disk.
1069 * @journal: Journal to act on.
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001070 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001071 * Given a journal_t structure which tells us which disk blocks contain
1072 * a journal, read the journal from disk to initialise the in-memory
1073 * structures.
1074 */
1075int journal_load(journal_t *journal)
1076{
1077 int err;
Badari Pulavartyea817392006-08-27 01:23:52 -07001078 journal_superblock_t *sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079
1080 err = load_superblock(journal);
1081 if (err)
1082 return err;
1083
Badari Pulavartyea817392006-08-27 01:23:52 -07001084 sb = journal->j_superblock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085 /* If this is a V2 superblock, then we have to check the
1086 * features flags on it. */
1087
1088 if (journal->j_format_version >= 2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 if ((sb->s_feature_ro_compat &
1090 ~cpu_to_be32(JFS_KNOWN_ROCOMPAT_FEATURES)) ||
1091 (sb->s_feature_incompat &
1092 ~cpu_to_be32(JFS_KNOWN_INCOMPAT_FEATURES))) {
1093 printk (KERN_WARNING
1094 "JBD: Unrecognised features on journal\n");
1095 return -EINVAL;
1096 }
1097 }
1098
1099 /* Let the recovery code check whether it needs to recover any
1100 * data from the journal. */
1101 if (journal_recover(journal))
1102 goto recovery_error;
1103
1104 /* OK, we've finished with the dynamic journal bits:
1105 * reinitialise the dynamic contents of the superblock in memory
1106 * and reset them on disk. */
1107 if (journal_reset(journal))
1108 goto recovery_error;
1109
1110 journal->j_flags &= ~JFS_ABORT;
1111 journal->j_flags |= JFS_LOADED;
1112 return 0;
1113
1114recovery_error:
1115 printk (KERN_WARNING "JBD: recovery failed\n");
1116 return -EIO;
1117}
1118
1119/**
1120 * void journal_destroy() - Release a journal_t structure.
1121 * @journal: Journal to act on.
1122 *
1123 * Release a journal_t structure once it is no longer in use by the
1124 * journaled object.
1125 */
1126void journal_destroy(journal_t *journal)
1127{
1128 /* Wait for the commit thread to wake up and die. */
1129 journal_kill_thread(journal);
1130
1131 /* Force a final log commit */
1132 if (journal->j_running_transaction)
1133 journal_commit_transaction(journal);
1134
1135 /* Force any old transactions to disk */
1136
1137 /* Totally anal locking here... */
1138 spin_lock(&journal->j_list_lock);
1139 while (journal->j_checkpoint_transactions != NULL) {
1140 spin_unlock(&journal->j_list_lock);
1141 log_do_checkpoint(journal);
1142 spin_lock(&journal->j_list_lock);
1143 }
1144
1145 J_ASSERT(journal->j_running_transaction == NULL);
1146 J_ASSERT(journal->j_committing_transaction == NULL);
1147 J_ASSERT(journal->j_checkpoint_transactions == NULL);
1148 spin_unlock(&journal->j_list_lock);
1149
1150 /* We can now mark the journal as empty. */
1151 journal->j_tail = 0;
1152 journal->j_tail_sequence = ++journal->j_transaction_sequence;
1153 if (journal->j_sb_buffer) {
1154 journal_update_superblock(journal, 1);
1155 brelse(journal->j_sb_buffer);
1156 }
1157
1158 if (journal->j_inode)
1159 iput(journal->j_inode);
1160 if (journal->j_revoke)
1161 journal_destroy_revoke(journal);
1162 kfree(journal->j_wbuf);
1163 kfree(journal);
1164}
1165
1166
1167/**
1168 *int journal_check_used_features () - Check if features specified are used.
1169 * @journal: Journal to check.
1170 * @compat: bitmask of compatible features
1171 * @ro: bitmask of features that force read-only mount
1172 * @incompat: bitmask of incompatible features
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001173 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 * Check whether the journal uses all of a given set of
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001175 * features. Return true (non-zero) if it does.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176 **/
1177
1178int journal_check_used_features (journal_t *journal, unsigned long compat,
1179 unsigned long ro, unsigned long incompat)
1180{
1181 journal_superblock_t *sb;
1182
1183 if (!compat && !ro && !incompat)
1184 return 1;
1185 if (journal->j_format_version == 1)
1186 return 0;
1187
1188 sb = journal->j_superblock;
1189
1190 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
1191 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
1192 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
1193 return 1;
1194
1195 return 0;
1196}
1197
1198/**
1199 * int journal_check_available_features() - Check feature set in journalling layer
1200 * @journal: Journal to check.
1201 * @compat: bitmask of compatible features
1202 * @ro: bitmask of features that force read-only mount
1203 * @incompat: bitmask of incompatible features
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001204 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205 * Check whether the journaling code supports the use of
1206 * all of a given set of features on this journal. Return true
1207 * (non-zero) if it can. */
1208
1209int journal_check_available_features (journal_t *journal, unsigned long compat,
1210 unsigned long ro, unsigned long incompat)
1211{
1212 journal_superblock_t *sb;
1213
1214 if (!compat && !ro && !incompat)
1215 return 1;
1216
1217 sb = journal->j_superblock;
1218
1219 /* We can support any known requested features iff the
1220 * superblock is in version 2. Otherwise we fail to support any
1221 * extended sb features. */
1222
1223 if (journal->j_format_version != 2)
1224 return 0;
1225
1226 if ((compat & JFS_KNOWN_COMPAT_FEATURES) == compat &&
1227 (ro & JFS_KNOWN_ROCOMPAT_FEATURES) == ro &&
1228 (incompat & JFS_KNOWN_INCOMPAT_FEATURES) == incompat)
1229 return 1;
1230
1231 return 0;
1232}
1233
1234/**
1235 * int journal_set_features () - Mark a given journal feature in the superblock
1236 * @journal: Journal to act on.
1237 * @compat: bitmask of compatible features
1238 * @ro: bitmask of features that force read-only mount
1239 * @incompat: bitmask of incompatible features
1240 *
1241 * Mark a given journal feature as present on the
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001242 * superblock. Returns true if the requested features could be set.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 *
1244 */
1245
1246int journal_set_features (journal_t *journal, unsigned long compat,
1247 unsigned long ro, unsigned long incompat)
1248{
1249 journal_superblock_t *sb;
1250
1251 if (journal_check_used_features(journal, compat, ro, incompat))
1252 return 1;
1253
1254 if (!journal_check_available_features(journal, compat, ro, incompat))
1255 return 0;
1256
1257 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1258 compat, ro, incompat);
1259
1260 sb = journal->j_superblock;
1261
1262 sb->s_feature_compat |= cpu_to_be32(compat);
1263 sb->s_feature_ro_compat |= cpu_to_be32(ro);
1264 sb->s_feature_incompat |= cpu_to_be32(incompat);
1265
1266 return 1;
1267}
1268
1269
1270/**
1271 * int journal_update_format () - Update on-disk journal structure.
1272 * @journal: Journal to act on.
1273 *
1274 * Given an initialised but unloaded journal struct, poke about in the
1275 * on-disk structure to update it to the most recent supported version.
1276 */
1277int journal_update_format (journal_t *journal)
1278{
1279 journal_superblock_t *sb;
1280 int err;
1281
1282 err = journal_get_superblock(journal);
1283 if (err)
1284 return err;
1285
1286 sb = journal->j_superblock;
1287
1288 switch (be32_to_cpu(sb->s_header.h_blocktype)) {
1289 case JFS_SUPERBLOCK_V2:
1290 return 0;
1291 case JFS_SUPERBLOCK_V1:
1292 return journal_convert_superblock_v1(journal, sb);
1293 default:
1294 break;
1295 }
1296 return -EINVAL;
1297}
1298
1299static int journal_convert_superblock_v1(journal_t *journal,
1300 journal_superblock_t *sb)
1301{
1302 int offset, blocksize;
1303 struct buffer_head *bh;
1304
1305 printk(KERN_WARNING
1306 "JBD: Converting superblock from version 1 to 2.\n");
1307
1308 /* Pre-initialise new fields to zero */
1309 offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
1310 blocksize = be32_to_cpu(sb->s_blocksize);
1311 memset(&sb->s_feature_compat, 0, blocksize-offset);
1312
1313 sb->s_nr_users = cpu_to_be32(1);
1314 sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2);
1315 journal->j_format_version = 2;
1316
1317 bh = journal->j_sb_buffer;
1318 BUFFER_TRACE(bh, "marking dirty");
1319 mark_buffer_dirty(bh);
1320 sync_dirty_buffer(bh);
1321 return 0;
1322}
1323
1324
1325/**
1326 * int journal_flush () - Flush journal
1327 * @journal: Journal to act on.
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001328 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329 * Flush all data for a given journal to disk and empty the journal.
1330 * Filesystems can use this when remounting readonly to ensure that
1331 * recovery does not need to happen on remount.
1332 */
1333
1334int journal_flush(journal_t *journal)
1335{
1336 int err = 0;
1337 transaction_t *transaction = NULL;
1338 unsigned long old_tail;
1339
1340 spin_lock(&journal->j_state_lock);
1341
1342 /* Force everything buffered to the log... */
1343 if (journal->j_running_transaction) {
1344 transaction = journal->j_running_transaction;
1345 __log_start_commit(journal, transaction->t_tid);
1346 } else if (journal->j_committing_transaction)
1347 transaction = journal->j_committing_transaction;
1348
1349 /* Wait for the log commit to complete... */
1350 if (transaction) {
1351 tid_t tid = transaction->t_tid;
1352
1353 spin_unlock(&journal->j_state_lock);
1354 log_wait_commit(journal, tid);
1355 } else {
1356 spin_unlock(&journal->j_state_lock);
1357 }
1358
1359 /* ...and flush everything in the log out to disk. */
1360 spin_lock(&journal->j_list_lock);
1361 while (!err && journal->j_checkpoint_transactions != NULL) {
1362 spin_unlock(&journal->j_list_lock);
1363 err = log_do_checkpoint(journal);
1364 spin_lock(&journal->j_list_lock);
1365 }
1366 spin_unlock(&journal->j_list_lock);
1367 cleanup_journal_tail(journal);
1368
1369 /* Finally, mark the journal as really needing no recovery.
1370 * This sets s_start==0 in the underlying superblock, which is
1371 * the magic code for a fully-recovered superblock. Any future
1372 * commits of data to the journal will restore the current
1373 * s_start value. */
1374 spin_lock(&journal->j_state_lock);
1375 old_tail = journal->j_tail;
1376 journal->j_tail = 0;
1377 spin_unlock(&journal->j_state_lock);
1378 journal_update_superblock(journal, 1);
1379 spin_lock(&journal->j_state_lock);
1380 journal->j_tail = old_tail;
1381
1382 J_ASSERT(!journal->j_running_transaction);
1383 J_ASSERT(!journal->j_committing_transaction);
1384 J_ASSERT(!journal->j_checkpoint_transactions);
1385 J_ASSERT(journal->j_head == journal->j_tail);
1386 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
1387 spin_unlock(&journal->j_state_lock);
1388 return err;
1389}
1390
1391/**
1392 * int journal_wipe() - Wipe journal contents
1393 * @journal: Journal to act on.
1394 * @write: flag (see below)
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001395 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001396 * Wipe out all of the contents of a journal, safely. This will produce
1397 * a warning if the journal contains any valid recovery information.
1398 * Must be called between journal_init_*() and journal_load().
1399 *
1400 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
1401 * we merely suppress recovery.
1402 */
1403
1404int journal_wipe(journal_t *journal, int write)
1405{
1406 journal_superblock_t *sb;
1407 int err = 0;
1408
1409 J_ASSERT (!(journal->j_flags & JFS_LOADED));
1410
1411 err = load_superblock(journal);
1412 if (err)
1413 return err;
1414
1415 sb = journal->j_superblock;
1416
1417 if (!journal->j_tail)
1418 goto no_recovery;
1419
1420 printk (KERN_WARNING "JBD: %s recovery information on journal\n",
1421 write ? "Clearing" : "Ignoring");
1422
1423 err = journal_skip_recovery(journal);
1424 if (write)
1425 journal_update_superblock(journal, 1);
1426
1427 no_recovery:
1428 return err;
1429}
1430
1431/*
1432 * journal_dev_name: format a character string to describe on what
1433 * device this journal is present.
1434 */
1435
Adrian Bunk022a4a72005-09-06 15:16:41 -07001436static const char *journal_dev_name(journal_t *journal, char *buffer)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437{
1438 struct block_device *bdev;
1439
1440 if (journal->j_inode)
1441 bdev = journal->j_inode->i_sb->s_bdev;
1442 else
1443 bdev = journal->j_dev;
1444
1445 return bdevname(bdev, buffer);
1446}
1447
1448/*
1449 * Journal abort has very specific semantics, which we describe
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001450 * for journal abort.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001451 *
1452 * Two internal function, which provide abort to te jbd layer
1453 * itself are here.
1454 */
1455
1456/*
1457 * Quick version for internal journal use (doesn't lock the journal).
1458 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
1459 * and don't attempt to make any other journal updates.
1460 */
Adrian Bunk53308382008-02-06 01:40:12 -08001461static void __journal_abort_hard(journal_t *journal)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462{
1463 transaction_t *transaction;
1464 char b[BDEVNAME_SIZE];
1465
1466 if (journal->j_flags & JFS_ABORT)
1467 return;
1468
1469 printk(KERN_ERR "Aborting journal on device %s.\n",
1470 journal_dev_name(journal, b));
1471
1472 spin_lock(&journal->j_state_lock);
1473 journal->j_flags |= JFS_ABORT;
1474 transaction = journal->j_running_transaction;
1475 if (transaction)
1476 __log_start_commit(journal, transaction->t_tid);
1477 spin_unlock(&journal->j_state_lock);
1478}
1479
1480/* Soft abort: record the abort error status in the journal superblock,
1481 * but don't do any other IO. */
Adrian Bunk022a4a72005-09-06 15:16:41 -07001482static void __journal_abort_soft (journal_t *journal, int errno)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483{
1484 if (journal->j_flags & JFS_ABORT)
1485 return;
1486
1487 if (!journal->j_errno)
1488 journal->j_errno = errno;
1489
1490 __journal_abort_hard(journal);
1491
1492 if (errno)
1493 journal_update_superblock(journal, 1);
1494}
1495
1496/**
1497 * void journal_abort () - Shutdown the journal immediately.
1498 * @journal: the journal to shutdown.
1499 * @errno: an error number to record in the journal indicating
1500 * the reason for the shutdown.
1501 *
1502 * Perform a complete, immediate shutdown of the ENTIRE
1503 * journal (not of a single transaction). This operation cannot be
1504 * undone without closing and reopening the journal.
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001505 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001506 * The journal_abort function is intended to support higher level error
1507 * recovery mechanisms such as the ext2/ext3 remount-readonly error
1508 * mode.
1509 *
1510 * Journal abort has very specific semantics. Any existing dirty,
1511 * unjournaled buffers in the main filesystem will still be written to
1512 * disk by bdflush, but the journaling mechanism will be suspended
1513 * immediately and no further transaction commits will be honoured.
1514 *
1515 * Any dirty, journaled buffers will be written back to disk without
1516 * hitting the journal. Atomicity cannot be guaranteed on an aborted
1517 * filesystem, but we _do_ attempt to leave as much data as possible
1518 * behind for fsck to use for cleanup.
1519 *
1520 * Any attempt to get a new transaction handle on a journal which is in
1521 * ABORT state will just result in an -EROFS error return. A
1522 * journal_stop on an existing handle will return -EIO if we have
1523 * entered abort state during the update.
1524 *
1525 * Recursive transactions are not disturbed by journal abort until the
1526 * final journal_stop, which will receive the -EIO error.
1527 *
1528 * Finally, the journal_abort call allows the caller to supply an errno
1529 * which will be recorded (if possible) in the journal superblock. This
1530 * allows a client to record failure conditions in the middle of a
1531 * transaction without having to complete the transaction to record the
1532 * failure to disk. ext3_error, for example, now uses this
1533 * functionality.
1534 *
1535 * Errors which originate from within the journaling layer will NOT
1536 * supply an errno; a null errno implies that absolutely no further
1537 * writes are done to the journal (unless there are any already in
1538 * progress).
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001539 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540 */
1541
1542void journal_abort(journal_t *journal, int errno)
1543{
1544 __journal_abort_soft(journal, errno);
1545}
1546
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001547/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548 * int journal_errno () - returns the journal's error state.
1549 * @journal: journal to examine.
1550 *
1551 * This is the errno numbet set with journal_abort(), the last
1552 * time the journal was mounted - if the journal was stopped
1553 * without calling abort this will be 0.
1554 *
1555 * If the journal has been aborted on this mount time -EROFS will
1556 * be returned.
1557 */
1558int journal_errno(journal_t *journal)
1559{
1560 int err;
1561
1562 spin_lock(&journal->j_state_lock);
1563 if (journal->j_flags & JFS_ABORT)
1564 err = -EROFS;
1565 else
1566 err = journal->j_errno;
1567 spin_unlock(&journal->j_state_lock);
1568 return err;
1569}
1570
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001571/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001572 * int journal_clear_err () - clears the journal's error state
1573 * @journal: journal to act on.
1574 *
1575 * An error must be cleared or Acked to take a FS out of readonly
1576 * mode.
1577 */
1578int journal_clear_err(journal_t *journal)
1579{
1580 int err = 0;
1581
1582 spin_lock(&journal->j_state_lock);
1583 if (journal->j_flags & JFS_ABORT)
1584 err = -EROFS;
1585 else
1586 journal->j_errno = 0;
1587 spin_unlock(&journal->j_state_lock);
1588 return err;
1589}
1590
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001591/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001592 * void journal_ack_err() - Ack journal err.
1593 * @journal: journal to act on.
1594 *
1595 * An error must be cleared or Acked to take a FS out of readonly
1596 * mode.
1597 */
1598void journal_ack_err(journal_t *journal)
1599{
1600 spin_lock(&journal->j_state_lock);
1601 if (journal->j_errno)
1602 journal->j_flags |= JFS_ACK_ERR;
1603 spin_unlock(&journal->j_state_lock);
1604}
1605
1606int journal_blocks_per_page(struct inode *inode)
1607{
1608 return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
1609}
1610
1611/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001612 * Journal_head storage management
1613 */
Christoph Lametere18b8902006-12-06 20:33:20 -08001614static struct kmem_cache *journal_head_cache;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001615#ifdef CONFIG_JBD_DEBUG
1616static atomic_t nr_journal_heads = ATOMIC_INIT(0);
1617#endif
1618
1619static int journal_init_journal_head_cache(void)
1620{
1621 int retval;
1622
Al Viro1076d172008-03-29 03:07:18 +00001623 J_ASSERT(journal_head_cache == NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624 journal_head_cache = kmem_cache_create("journal_head",
1625 sizeof(struct journal_head),
1626 0, /* offset */
Mel Gormane12ba742007-10-16 01:25:52 -07001627 SLAB_TEMPORARY, /* flags */
Paul Mundt20c2df82007-07-20 10:11:58 +09001628 NULL); /* ctor */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001629 retval = 0;
Al Viro1076d172008-03-29 03:07:18 +00001630 if (!journal_head_cache) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631 retval = -ENOMEM;
1632 printk(KERN_EMERG "JBD: no memory for journal_head cache\n");
1633 }
1634 return retval;
1635}
1636
1637static void journal_destroy_journal_head_cache(void)
1638{
1639 J_ASSERT(journal_head_cache != NULL);
1640 kmem_cache_destroy(journal_head_cache);
1641 journal_head_cache = NULL;
1642}
1643
1644/*
1645 * journal_head splicing and dicing
1646 */
1647static struct journal_head *journal_alloc_journal_head(void)
1648{
1649 struct journal_head *ret;
1650 static unsigned long last_warning;
1651
1652#ifdef CONFIG_JBD_DEBUG
1653 atomic_inc(&nr_journal_heads);
1654#endif
1655 ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS);
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001656 if (ret == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001657 jbd_debug(1, "out of memory for journal_head\n");
1658 if (time_after(jiffies, last_warning + 5*HZ)) {
1659 printk(KERN_NOTICE "ENOMEM in %s, retrying.\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -07001660 __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001661 last_warning = jiffies;
1662 }
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001663 while (ret == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001664 yield();
1665 ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS);
1666 }
1667 }
1668 return ret;
1669}
1670
1671static void journal_free_journal_head(struct journal_head *jh)
1672{
1673#ifdef CONFIG_JBD_DEBUG
1674 atomic_dec(&nr_journal_heads);
Randy Dunlapc9cf5522006-06-27 02:53:52 -07001675 memset(jh, JBD_POISON_FREE, sizeof(*jh));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001676#endif
1677 kmem_cache_free(journal_head_cache, jh);
1678}
1679
1680/*
1681 * A journal_head is attached to a buffer_head whenever JBD has an
1682 * interest in the buffer.
1683 *
1684 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
1685 * is set. This bit is tested in core kernel code where we need to take
1686 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
1687 * there.
1688 *
1689 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
1690 *
1691 * When a buffer has its BH_JBD bit set it is immune from being released by
1692 * core kernel code, mainly via ->b_count.
1693 *
1694 * A journal_head may be detached from its buffer_head when the journal_head's
1695 * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL.
1696 * Various places in JBD call journal_remove_journal_head() to indicate that the
1697 * journal_head can be dropped if needed.
1698 *
1699 * Various places in the kernel want to attach a journal_head to a buffer_head
1700 * _before_ attaching the journal_head to a transaction. To protect the
1701 * journal_head in this situation, journal_add_journal_head elevates the
1702 * journal_head's b_jcount refcount by one. The caller must call
1703 * journal_put_journal_head() to undo this.
1704 *
1705 * So the typical usage would be:
1706 *
1707 * (Attach a journal_head if needed. Increments b_jcount)
1708 * struct journal_head *jh = journal_add_journal_head(bh);
1709 * ...
1710 * jh->b_transaction = xxx;
1711 * journal_put_journal_head(jh);
1712 *
1713 * Now, the journal_head's b_jcount is zero, but it is safe from being released
1714 * because it has a non-zero b_transaction.
1715 */
1716
1717/*
1718 * Give a buffer_head a journal_head.
1719 *
1720 * Doesn't need the journal lock.
1721 * May sleep.
1722 */
1723struct journal_head *journal_add_journal_head(struct buffer_head *bh)
1724{
1725 struct journal_head *jh;
1726 struct journal_head *new_jh = NULL;
1727
1728repeat:
1729 if (!buffer_jbd(bh)) {
1730 new_jh = journal_alloc_journal_head();
1731 memset(new_jh, 0, sizeof(*new_jh));
1732 }
1733
1734 jbd_lock_bh_journal_head(bh);
1735 if (buffer_jbd(bh)) {
1736 jh = bh2jh(bh);
1737 } else {
1738 J_ASSERT_BH(bh,
1739 (atomic_read(&bh->b_count) > 0) ||
1740 (bh->b_page && bh->b_page->mapping));
1741
1742 if (!new_jh) {
1743 jbd_unlock_bh_journal_head(bh);
1744 goto repeat;
1745 }
1746
1747 jh = new_jh;
1748 new_jh = NULL; /* We consumed it */
1749 set_buffer_jbd(bh);
1750 bh->b_private = jh;
1751 jh->b_bh = bh;
1752 get_bh(bh);
1753 BUFFER_TRACE(bh, "added journal_head");
1754 }
1755 jh->b_jcount++;
1756 jbd_unlock_bh_journal_head(bh);
1757 if (new_jh)
1758 journal_free_journal_head(new_jh);
1759 return bh->b_private;
1760}
1761
1762/*
1763 * Grab a ref against this buffer_head's journal_head. If it ended up not
1764 * having a journal_head, return NULL
1765 */
1766struct journal_head *journal_grab_journal_head(struct buffer_head *bh)
1767{
1768 struct journal_head *jh = NULL;
1769
1770 jbd_lock_bh_journal_head(bh);
1771 if (buffer_jbd(bh)) {
1772 jh = bh2jh(bh);
1773 jh->b_jcount++;
1774 }
1775 jbd_unlock_bh_journal_head(bh);
1776 return jh;
1777}
1778
1779static void __journal_remove_journal_head(struct buffer_head *bh)
1780{
1781 struct journal_head *jh = bh2jh(bh);
1782
1783 J_ASSERT_JH(jh, jh->b_jcount >= 0);
1784
1785 get_bh(bh);
1786 if (jh->b_jcount == 0) {
1787 if (jh->b_transaction == NULL &&
1788 jh->b_next_transaction == NULL &&
1789 jh->b_cp_transaction == NULL) {
1790 J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
1791 J_ASSERT_BH(bh, buffer_jbd(bh));
1792 J_ASSERT_BH(bh, jh2bh(jh) == bh);
1793 BUFFER_TRACE(bh, "remove journal_head");
1794 if (jh->b_frozen_data) {
1795 printk(KERN_WARNING "%s: freeing "
1796 "b_frozen_data\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -07001797 __func__);
Mingming Caoc089d492007-10-16 18:38:25 -04001798 jbd_free(jh->b_frozen_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 }
1800 if (jh->b_committed_data) {
1801 printk(KERN_WARNING "%s: freeing "
1802 "b_committed_data\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -07001803 __func__);
Mingming Caoc089d492007-10-16 18:38:25 -04001804 jbd_free(jh->b_committed_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001805 }
1806 bh->b_private = NULL;
1807 jh->b_bh = NULL; /* debug, really */
1808 clear_buffer_jbd(bh);
1809 __brelse(bh);
1810 journal_free_journal_head(jh);
1811 } else {
1812 BUFFER_TRACE(bh, "journal_head was locked");
1813 }
1814 }
1815}
1816
1817/*
1818 * journal_remove_journal_head(): if the buffer isn't attached to a transaction
1819 * and has a zero b_jcount then remove and release its journal_head. If we did
1820 * see that the buffer is not used by any transaction we also "logically"
1821 * decrement ->b_count.
1822 *
1823 * We in fact take an additional increment on ->b_count as a convenience,
1824 * because the caller usually wants to do additional things with the bh
1825 * after calling here.
1826 * The caller of journal_remove_journal_head() *must* run __brelse(bh) at some
1827 * time. Once the caller has run __brelse(), the buffer is eligible for
1828 * reaping by try_to_free_buffers().
1829 */
1830void journal_remove_journal_head(struct buffer_head *bh)
1831{
1832 jbd_lock_bh_journal_head(bh);
1833 __journal_remove_journal_head(bh);
1834 jbd_unlock_bh_journal_head(bh);
1835}
1836
1837/*
1838 * Drop a reference on the passed journal_head. If it fell to zero then try to
1839 * release the journal_head from the buffer_head.
1840 */
1841void journal_put_journal_head(struct journal_head *jh)
1842{
1843 struct buffer_head *bh = jh2bh(jh);
1844
1845 jbd_lock_bh_journal_head(bh);
1846 J_ASSERT_JH(jh, jh->b_jcount > 0);
1847 --jh->b_jcount;
1848 if (!jh->b_jcount && !jh->b_transaction) {
1849 __journal_remove_journal_head(bh);
1850 __brelse(bh);
1851 }
1852 jbd_unlock_bh_journal_head(bh);
1853}
1854
1855/*
Jose R. Santosc2a91592007-10-18 23:39:22 -07001856 * debugfs tunables
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 */
Jose R. Santosc2a91592007-10-18 23:39:22 -07001858#ifdef CONFIG_JBD_DEBUG
1859
1860u8 journal_enable_debug __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861EXPORT_SYMBOL(journal_enable_debug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862
Jose R. Santosc2a91592007-10-18 23:39:22 -07001863static struct dentry *jbd_debugfs_dir;
1864static struct dentry *jbd_debug;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001865
Jose R. Santosc2a91592007-10-18 23:39:22 -07001866static void __init jbd_create_debugfs_entry(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867{
Jose R. Santosc2a91592007-10-18 23:39:22 -07001868 jbd_debugfs_dir = debugfs_create_dir("jbd", NULL);
1869 if (jbd_debugfs_dir)
1870 jbd_debug = debugfs_create_u8("jbd-debug", S_IRUGO,
1871 jbd_debugfs_dir,
1872 &journal_enable_debug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873}
1874
Jose R. Santosc2a91592007-10-18 23:39:22 -07001875static void __exit jbd_remove_debugfs_entry(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001876{
Jose R. Santosc2a91592007-10-18 23:39:22 -07001877 debugfs_remove(jbd_debug);
1878 debugfs_remove(jbd_debugfs_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001879}
1880
1881#else
1882
Jose R. Santosc2a91592007-10-18 23:39:22 -07001883static inline void jbd_create_debugfs_entry(void)
1884{
1885}
1886
1887static inline void jbd_remove_debugfs_entry(void)
1888{
1889}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001890
1891#endif
1892
Christoph Lametere18b8902006-12-06 20:33:20 -08001893struct kmem_cache *jbd_handle_cache;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001894
1895static int __init journal_init_handle_cache(void)
1896{
1897 jbd_handle_cache = kmem_cache_create("journal_handle",
1898 sizeof(handle_t),
1899 0, /* offset */
Mel Gormane12ba742007-10-16 01:25:52 -07001900 SLAB_TEMPORARY, /* flags */
Paul Mundt20c2df82007-07-20 10:11:58 +09001901 NULL); /* ctor */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902 if (jbd_handle_cache == NULL) {
1903 printk(KERN_EMERG "JBD: failed to create handle cache\n");
1904 return -ENOMEM;
1905 }
1906 return 0;
1907}
1908
1909static void journal_destroy_handle_cache(void)
1910{
1911 if (jbd_handle_cache)
1912 kmem_cache_destroy(jbd_handle_cache);
1913}
1914
1915/*
1916 * Module startup and shutdown
1917 */
1918
1919static int __init journal_init_caches(void)
1920{
1921 int ret;
1922
1923 ret = journal_init_revoke_caches();
1924 if (ret == 0)
1925 ret = journal_init_journal_head_cache();
1926 if (ret == 0)
1927 ret = journal_init_handle_cache();
1928 return ret;
1929}
1930
1931static void journal_destroy_caches(void)
1932{
1933 journal_destroy_revoke_caches();
1934 journal_destroy_journal_head_cache();
1935 journal_destroy_handle_cache();
1936}
1937
1938static int __init journal_init(void)
1939{
1940 int ret;
1941
Alexey Dobriyan2aed3482006-09-27 01:49:28 -07001942 BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
Adrian Bunk022a4a72005-09-06 15:16:41 -07001943
Linus Torvalds1da177e2005-04-16 15:20:36 -07001944 ret = journal_init_caches();
1945 if (ret != 0)
1946 journal_destroy_caches();
Jose R. Santosc2a91592007-10-18 23:39:22 -07001947 jbd_create_debugfs_entry();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001948 return ret;
1949}
1950
1951static void __exit journal_exit(void)
1952{
1953#ifdef CONFIG_JBD_DEBUG
1954 int n = atomic_read(&nr_journal_heads);
1955 if (n)
1956 printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n);
1957#endif
Jose R. Santosc2a91592007-10-18 23:39:22 -07001958 jbd_remove_debugfs_entry();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001959 journal_destroy_caches();
1960}
1961
1962MODULE_LICENSE("GPL");
1963module_init(journal_init);
1964module_exit(journal_exit);
1965