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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);
Stefan Schmidtff5e4b52009-11-12 09:53:50 +010076EXPORT_SYMBOL(log_start_commit);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077EXPORT_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,
Jan Kara9c28cbc2009-08-03 19:21:00 +0200280 unsigned int 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);
dingdinghuaf1015c42009-07-15 21:42:05 +0200291 journal_t *journal = transaction->t_journal;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292
293 /*
294 * The buffer really shouldn't be locked: only the current committing
295 * transaction is allowed to write it, so nobody else is allowed
296 * to do any IO.
297 *
298 * akpm: except if we're journalling data, and write() output is
299 * also part of a shared mapping, and another thread has
300 * decided to launch a writepage() against this buffer.
301 */
302 J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
303
304 new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
dingdinghuaf1015c42009-07-15 21:42:05 +0200305 /* keep subsequent assertions sane */
306 new_bh->b_state = 0;
307 init_buffer(new_bh, NULL, NULL);
308 atomic_set(&new_bh->b_count, 1);
309 new_jh = journal_add_journal_head(new_bh); /* This sleeps */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310
311 /*
312 * If a new transaction has already done a buffer copy-out, then
313 * we use that version of the data for the commit.
314 */
315 jbd_lock_bh_state(bh_in);
316repeat:
317 if (jh_in->b_frozen_data) {
318 done_copy_out = 1;
319 new_page = virt_to_page(jh_in->b_frozen_data);
320 new_offset = offset_in_page(jh_in->b_frozen_data);
321 } else {
322 new_page = jh2bh(jh_in)->b_page;
323 new_offset = offset_in_page(jh2bh(jh_in)->b_data);
324 }
325
326 mapped_data = kmap_atomic(new_page, KM_USER0);
327 /*
328 * Check for escaping
329 */
330 if (*((__be32 *)(mapped_data + new_offset)) ==
331 cpu_to_be32(JFS_MAGIC_NUMBER)) {
332 need_copy_out = 1;
333 do_escape = 1;
334 }
335 kunmap_atomic(mapped_data, KM_USER0);
336
337 /*
338 * Do we need to do a data copy?
339 */
340 if (need_copy_out && !done_copy_out) {
341 char *tmp;
342
343 jbd_unlock_bh_state(bh_in);
Mingming Caoc089d492007-10-16 18:38:25 -0400344 tmp = jbd_alloc(bh_in->b_size, GFP_NOFS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 jbd_lock_bh_state(bh_in);
346 if (jh_in->b_frozen_data) {
Mingming Caoc089d492007-10-16 18:38:25 -0400347 jbd_free(tmp, bh_in->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 goto repeat;
349 }
350
351 jh_in->b_frozen_data = tmp;
352 mapped_data = kmap_atomic(new_page, KM_USER0);
353 memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size);
354 kunmap_atomic(mapped_data, KM_USER0);
355
356 new_page = virt_to_page(tmp);
357 new_offset = offset_in_page(tmp);
358 done_copy_out = 1;
359 }
360
361 /*
362 * Did we need to do an escaping? Now we've done all the
363 * copying, we can finally do so.
364 */
365 if (do_escape) {
366 mapped_data = kmap_atomic(new_page, KM_USER0);
367 *((unsigned int *)(mapped_data + new_offset)) = 0;
368 kunmap_atomic(mapped_data, KM_USER0);
369 }
370
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 set_bh_page(new_bh, new_page, new_offset);
372 new_jh->b_transaction = NULL;
373 new_bh->b_size = jh2bh(jh_in)->b_size;
374 new_bh->b_bdev = transaction->t_journal->j_dev;
375 new_bh->b_blocknr = blocknr;
376 set_buffer_mapped(new_bh);
377 set_buffer_dirty(new_bh);
378
379 *jh_out = new_jh;
380
381 /*
382 * The to-be-written buffer needs to get moved to the io queue,
383 * and the original buffer whose contents we are shadowing or
384 * copying is moved to the transaction's shadow queue.
385 */
386 JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
dingdinghuaf1015c42009-07-15 21:42:05 +0200387 spin_lock(&journal->j_list_lock);
388 __journal_file_buffer(jh_in, transaction, BJ_Shadow);
389 spin_unlock(&journal->j_list_lock);
390 jbd_unlock_bh_state(bh_in);
391
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 JBUFFER_TRACE(new_jh, "file as BJ_IO");
393 journal_file_buffer(new_jh, transaction, BJ_IO);
394
395 return do_escape | (done_copy_out << 1);
396}
397
398/*
399 * Allocation code for the journal file. Manage the space left in the
400 * journal, so that we can begin checkpointing when appropriate.
401 */
402
403/*
404 * __log_space_left: Return the number of free blocks left in the journal.
405 *
406 * Called with the journal already locked.
407 *
408 * Called under j_state_lock
409 */
410
411int __log_space_left(journal_t *journal)
412{
413 int left = journal->j_free;
414
415 assert_spin_locked(&journal->j_state_lock);
416
417 /*
418 * Be pessimistic here about the number of those free blocks which
419 * might be required for log descriptor control blocks.
420 */
421
422#define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */
423
424 left -= MIN_LOG_RESERVED_BLOCKS;
425
426 if (left <= 0)
427 return 0;
428 left -= (left >> 3);
429 return left;
430}
431
432/*
Jan Kara8fe4cd02009-02-11 13:04:25 -0800433 * Called under j_state_lock. Returns true if a transaction commit was started.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 */
435int __log_start_commit(journal_t *journal, tid_t target)
436{
437 /*
438 * Are we already doing a recent enough commit?
439 */
440 if (!tid_geq(journal->j_commit_request, target)) {
441 /*
442 * We want a new commit: OK, mark the request and wakup the
443 * commit thread. We do _not_ do the commit ourselves.
444 */
445
446 journal->j_commit_request = target;
447 jbd_debug(1, "JBD: requesting commit %d/%d\n",
448 journal->j_commit_request,
449 journal->j_commit_sequence);
450 wake_up(&journal->j_wait_commit);
451 return 1;
452 }
453 return 0;
454}
455
456int log_start_commit(journal_t *journal, tid_t tid)
457{
458 int ret;
459
460 spin_lock(&journal->j_state_lock);
461 ret = __log_start_commit(journal, tid);
462 spin_unlock(&journal->j_state_lock);
463 return ret;
464}
465
466/*
467 * Force and wait upon a commit if the calling process is not within
468 * transaction. This is used for forcing out undo-protected data which contains
469 * bitmaps, when the fs is running out of space.
470 *
471 * We can only force the running transaction if we don't have an active handle;
472 * otherwise, we will deadlock.
473 *
474 * Returns true if a transaction was started.
475 */
476int journal_force_commit_nested(journal_t *journal)
477{
478 transaction_t *transaction = NULL;
479 tid_t tid;
480
481 spin_lock(&journal->j_state_lock);
482 if (journal->j_running_transaction && !current->journal_info) {
483 transaction = journal->j_running_transaction;
484 __log_start_commit(journal, transaction->t_tid);
485 } else if (journal->j_committing_transaction)
486 transaction = journal->j_committing_transaction;
487
488 if (!transaction) {
489 spin_unlock(&journal->j_state_lock);
490 return 0; /* Nothing to retry */
491 }
492
493 tid = transaction->t_tid;
494 spin_unlock(&journal->j_state_lock);
495 log_wait_commit(journal, tid);
496 return 1;
497}
498
499/*
500 * Start a commit of the current running transaction (if any). Returns true
Jan Kara8fe4cd02009-02-11 13:04:25 -0800501 * if a transaction is going to be committed (or is currently already
502 * committing), and fills its tid in at *ptid
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 */
504int journal_start_commit(journal_t *journal, tid_t *ptid)
505{
506 int ret = 0;
507
508 spin_lock(&journal->j_state_lock);
509 if (journal->j_running_transaction) {
510 tid_t tid = journal->j_running_transaction->t_tid;
511
Jan Kara8fe4cd02009-02-11 13:04:25 -0800512 __log_start_commit(journal, tid);
513 /* There's a running transaction and we've just made sure
514 * it's commit has been scheduled. */
515 if (ptid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 *ptid = tid;
Jan Kara8fe4cd02009-02-11 13:04:25 -0800517 ret = 1;
518 } else if (journal->j_committing_transaction) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 /*
520 * If ext3_write_super() recently started a commit, then we
521 * have to wait for completion of that transaction
522 */
Jan Kara8fe4cd02009-02-11 13:04:25 -0800523 if (ptid)
524 *ptid = journal->j_committing_transaction->t_tid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 ret = 1;
526 }
527 spin_unlock(&journal->j_state_lock);
528 return ret;
529}
530
531/*
532 * Wait for a specified commit to complete.
533 * The caller may not hold the journal lock.
534 */
535int log_wait_commit(journal_t *journal, tid_t tid)
536{
537 int err = 0;
538
539#ifdef CONFIG_JBD_DEBUG
540 spin_lock(&journal->j_state_lock);
541 if (!tid_geq(journal->j_commit_request, tid)) {
542 printk(KERN_EMERG
543 "%s: error: j_commit_request=%d, tid=%d\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700544 __func__, journal->j_commit_request, tid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 }
546 spin_unlock(&journal->j_state_lock);
547#endif
548 spin_lock(&journal->j_state_lock);
549 while (tid_gt(tid, journal->j_commit_sequence)) {
550 jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n",
551 tid, journal->j_commit_sequence);
552 wake_up(&journal->j_wait_commit);
553 spin_unlock(&journal->j_state_lock);
554 wait_event(journal->j_wait_done_commit,
555 !tid_gt(tid, journal->j_commit_sequence));
556 spin_lock(&journal->j_state_lock);
557 }
558 spin_unlock(&journal->j_state_lock);
559
560 if (unlikely(is_journal_aborted(journal))) {
561 printk(KERN_EMERG "journal commit I/O error\n");
562 err = -EIO;
563 }
564 return err;
565}
566
567/*
568 * Log buffer allocation routines:
569 */
570
Jan Kara9c28cbc2009-08-03 19:21:00 +0200571int journal_next_log_block(journal_t *journal, unsigned int *retp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572{
Jan Kara9c28cbc2009-08-03 19:21:00 +0200573 unsigned int blocknr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574
575 spin_lock(&journal->j_state_lock);
576 J_ASSERT(journal->j_free > 1);
577
578 blocknr = journal->j_head;
579 journal->j_head++;
580 journal->j_free--;
581 if (journal->j_head == journal->j_last)
582 journal->j_head = journal->j_first;
583 spin_unlock(&journal->j_state_lock);
584 return journal_bmap(journal, blocknr, retp);
585}
586
587/*
588 * Conversion of logical to physical block numbers for the journal
589 *
590 * On external journals the journal blocks are identity-mapped, so
591 * this is a no-op. If needed, we can use j_blk_offset - everything is
592 * ready.
593 */
Jan Kara9c28cbc2009-08-03 19:21:00 +0200594int journal_bmap(journal_t *journal, unsigned int blocknr,
595 unsigned int *retp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596{
597 int err = 0;
Jan Kara9c28cbc2009-08-03 19:21:00 +0200598 unsigned int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599
600 if (journal->j_inode) {
601 ret = bmap(journal->j_inode, blocknr);
602 if (ret)
603 *retp = ret;
604 else {
605 char b[BDEVNAME_SIZE];
606
607 printk(KERN_ALERT "%s: journal block not found "
Jan Kara9c28cbc2009-08-03 19:21:00 +0200608 "at offset %u on %s\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700609 __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 blocknr,
611 bdevname(journal->j_dev, b));
612 err = -EIO;
613 __journal_abort_soft(journal, err);
614 }
615 } else {
616 *retp = blocknr; /* +journal->j_blk_offset */
617 }
618 return err;
619}
620
621/*
622 * We play buffer_head aliasing tricks to write data/metadata blocks to
623 * the journal without copying their contents, but for journal
624 * descriptor blocks we do need to generate bona fide buffers.
625 *
626 * After the caller of journal_get_descriptor_buffer() has finished modifying
627 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
628 * But we don't bother doing that, so there will be coherency problems with
629 * mmaps of blockdevs which hold live JBD-controlled filesystems.
630 */
631struct journal_head *journal_get_descriptor_buffer(journal_t *journal)
632{
633 struct buffer_head *bh;
Jan Kara9c28cbc2009-08-03 19:21:00 +0200634 unsigned int blocknr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 int err;
636
637 err = journal_next_log_block(journal, &blocknr);
638
639 if (err)
640 return NULL;
641
642 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
Jan Karaecca9af2009-04-02 16:57:13 -0700643 if (!bh)
644 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 lock_buffer(bh);
646 memset(bh->b_data, 0, journal->j_blocksize);
647 set_buffer_uptodate(bh);
648 unlock_buffer(bh);
649 BUFFER_TRACE(bh, "return this buffer");
650 return journal_add_journal_head(bh);
651}
652
653/*
654 * Management for journal control blocks: functions to create and
655 * destroy journal_t structures, and to initialise and read existing
656 * journal blocks from disk. */
657
658/* First: create and setup a journal_t object in memory. We initialise
659 * very few fields yet: that has to wait until we have created the
660 * journal structures from from scratch, or loaded them from disk. */
661
662static journal_t * journal_init_common (void)
663{
664 journal_t *journal;
665 int err;
666
Mingming Cao8c3478a2007-10-18 23:39:20 -0700667 journal = kzalloc(sizeof(*journal), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 if (!journal)
669 goto fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670
671 init_waitqueue_head(&journal->j_wait_transaction_locked);
672 init_waitqueue_head(&journal->j_wait_logspace);
673 init_waitqueue_head(&journal->j_wait_done_commit);
674 init_waitqueue_head(&journal->j_wait_checkpoint);
675 init_waitqueue_head(&journal->j_wait_commit);
676 init_waitqueue_head(&journal->j_wait_updates);
Arjan van de Ven2c68ee72006-03-23 03:00:35 -0800677 mutex_init(&journal->j_barrier);
678 mutex_init(&journal->j_checkpoint_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 spin_lock_init(&journal->j_revoke_lock);
680 spin_lock_init(&journal->j_list_lock);
681 spin_lock_init(&journal->j_state_lock);
682
683 journal->j_commit_interval = (HZ * JBD_DEFAULT_MAX_COMMIT_AGE);
684
685 /* The journal is marked for error until we succeed with recovery! */
686 journal->j_flags = JFS_ABORT;
687
688 /* Set up a default-sized revoke table for the new mount. */
689 err = journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
690 if (err) {
691 kfree(journal);
692 goto fail;
693 }
694 return journal;
695fail:
696 return NULL;
697}
698
699/* journal_init_dev and journal_init_inode:
700 *
701 * Create a journal structure assigned some fixed set of disk blocks to
702 * the journal. We don't actually touch those disk blocks yet, but we
703 * need to set up all of the mapping information to tell the journaling
704 * system where the journal blocks are.
705 *
706 */
707
708/**
Randy Dunlap0cf01f62008-03-19 17:00:44 -0700709 * journal_t * journal_init_dev() - creates and initialises a journal structure
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 * @bdev: Block device on which to create the journal
711 * @fs_dev: Device which hold journalled filesystem for this journal.
712 * @start: Block nr Start of journal.
Eric Sandeen37ed3222006-09-27 01:49:31 -0700713 * @len: Length of the journal in blocks.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 * @blocksize: blocksize of journalling device
Randy Dunlap0cf01f62008-03-19 17:00:44 -0700715 *
716 * Returns: a newly created journal_t *
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700717 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 * journal_init_dev creates a journal which maps a fixed contiguous
719 * range of blocks on an arbitrary block device.
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700720 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721 */
722journal_t * journal_init_dev(struct block_device *bdev,
723 struct block_device *fs_dev,
724 int start, int len, int blocksize)
725{
726 journal_t *journal = journal_init_common();
727 struct buffer_head *bh;
728 int n;
729
730 if (!journal)
731 return NULL;
732
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 /* journal descriptor can store up to n blocks -bzzz */
Zoltan Menyhartd1807792006-09-29 01:58:40 -0700734 journal->j_blocksize = blocksize;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 n = journal->j_blocksize / sizeof(journal_block_tag_t);
736 journal->j_wbufsize = n;
737 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
738 if (!journal->j_wbuf) {
739 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700740 __func__);
Jan Karaecca9af2009-04-02 16:57:13 -0700741 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 }
Zoltan Menyhartd1807792006-09-29 01:58:40 -0700743 journal->j_dev = bdev;
744 journal->j_fs_dev = fs_dev;
745 journal->j_blk_offset = start;
746 journal->j_maxlen = len;
747
748 bh = __getblk(journal->j_dev, start, journal->j_blocksize);
Jan Karaecca9af2009-04-02 16:57:13 -0700749 if (!bh) {
750 printk(KERN_ERR
751 "%s: Cannot get buffer for journal superblock\n",
752 __func__);
753 goto out_err;
754 }
Zoltan Menyhartd1807792006-09-29 01:58:40 -0700755 journal->j_sb_buffer = bh;
756 journal->j_superblock = (journal_superblock_t *)bh->b_data;
Jan Karaecca9af2009-04-02 16:57:13 -0700757
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 return journal;
Jan Karaecca9af2009-04-02 16:57:13 -0700759out_err:
Tao Ma7b02bec2009-11-10 17:13:22 +0800760 kfree(journal->j_wbuf);
Jan Karaecca9af2009-04-02 16:57:13 -0700761 kfree(journal);
762 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763}
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700764
765/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 * journal_t * journal_init_inode () - creates a journal which maps to a inode.
767 * @inode: An inode to create the journal in
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700768 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 * journal_init_inode creates a journal which maps an on-disk inode as
770 * the journal. The inode must exist already, must support bmap() and
771 * must have all data blocks preallocated.
772 */
773journal_t * journal_init_inode (struct inode *inode)
774{
775 struct buffer_head *bh;
776 journal_t *journal = journal_init_common();
777 int err;
778 int n;
Jan Kara9c28cbc2009-08-03 19:21:00 +0200779 unsigned int blocknr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780
781 if (!journal)
782 return NULL;
783
784 journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
785 journal->j_inode = inode;
786 jbd_debug(1,
787 "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700788 journal, inode->i_sb->s_id, inode->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789 (long long) inode->i_size,
790 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
791
792 journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
793 journal->j_blocksize = inode->i_sb->s_blocksize;
794
795 /* journal descriptor can store up to n blocks -bzzz */
796 n = journal->j_blocksize / sizeof(journal_block_tag_t);
797 journal->j_wbufsize = n;
798 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
799 if (!journal->j_wbuf) {
800 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700801 __func__);
Jan Karaecca9af2009-04-02 16:57:13 -0700802 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 }
804
805 err = journal_bmap(journal, 0, &blocknr);
806 /* If that failed, give up */
807 if (err) {
808 printk(KERN_ERR "%s: Cannnot locate journal superblock\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700809 __func__);
Jan Karaecca9af2009-04-02 16:57:13 -0700810 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 }
812
813 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
Jan Karaecca9af2009-04-02 16:57:13 -0700814 if (!bh) {
815 printk(KERN_ERR
816 "%s: Cannot get buffer for journal superblock\n",
817 __func__);
818 goto out_err;
819 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 journal->j_sb_buffer = bh;
821 journal->j_superblock = (journal_superblock_t *)bh->b_data;
822
823 return journal;
Jan Karaecca9af2009-04-02 16:57:13 -0700824out_err:
Tao Ma7b02bec2009-11-10 17:13:22 +0800825 kfree(journal->j_wbuf);
Jan Karaecca9af2009-04-02 16:57:13 -0700826 kfree(journal);
827 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828}
829
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700830/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 * If the journal init or create aborts, we need to mark the journal
832 * superblock as being NULL to prevent the journal destroy from writing
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700833 * back a bogus superblock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 */
835static void journal_fail_superblock (journal_t *journal)
836{
837 struct buffer_head *bh = journal->j_sb_buffer;
838 brelse(bh);
839 journal->j_sb_buffer = NULL;
840}
841
842/*
843 * Given a journal_t structure, initialise the various fields for
844 * startup of a new journaling session. We use this both when creating
845 * a journal, and after recovering an old journal to reset it for
846 * subsequent use.
847 */
848
849static int journal_reset(journal_t *journal)
850{
851 journal_superblock_t *sb = journal->j_superblock;
Jan Kara9c28cbc2009-08-03 19:21:00 +0200852 unsigned int first, last;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853
854 first = be32_to_cpu(sb->s_first);
855 last = be32_to_cpu(sb->s_maxlen);
Jan Kara7447a662009-07-15 20:36:08 +0200856 if (first + JFS_MIN_JOURNAL_BLOCKS > last + 1) {
Jan Kara9c28cbc2009-08-03 19:21:00 +0200857 printk(KERN_ERR "JBD: Journal too short (blocks %u-%u).\n",
Jan Kara7447a662009-07-15 20:36:08 +0200858 first, last);
859 journal_fail_superblock(journal);
860 return -EINVAL;
861 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862
863 journal->j_first = first;
864 journal->j_last = last;
865
866 journal->j_head = first;
867 journal->j_tail = first;
868 journal->j_free = last - first;
869
870 journal->j_tail_sequence = journal->j_transaction_sequence;
871 journal->j_commit_sequence = journal->j_transaction_sequence - 1;
872 journal->j_commit_request = journal->j_commit_sequence;
873
874 journal->j_max_transaction_buffers = journal->j_maxlen / 4;
875
876 /* Add the dynamic fields and write it to disk. */
877 journal_update_superblock(journal, 1);
Pavel Emelianov97f06782007-05-08 00:30:42 -0700878 return journal_start_thread(journal);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879}
880
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700881/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882 * int journal_create() - Initialise the new journal file
883 * @journal: Journal to create. This structure must have been initialised
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700884 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 * Given a journal_t structure which tells us which disk blocks we can
886 * use, create a new journal superblock and initialise all of the
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700887 * journal fields from scratch.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 **/
889int journal_create(journal_t *journal)
890{
Jan Kara9c28cbc2009-08-03 19:21:00 +0200891 unsigned int blocknr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 struct buffer_head *bh;
893 journal_superblock_t *sb;
894 int i, err;
895
896 if (journal->j_maxlen < JFS_MIN_JOURNAL_BLOCKS) {
897 printk (KERN_ERR "Journal length (%d blocks) too short.\n",
898 journal->j_maxlen);
899 journal_fail_superblock(journal);
900 return -EINVAL;
901 }
902
903 if (journal->j_inode == NULL) {
904 /*
905 * We don't know what block to start at!
906 */
907 printk(KERN_EMERG
908 "%s: creation of journal on external device!\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -0700909 __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 BUG();
911 }
912
913 /* Zero out the entire journal on disk. We cannot afford to
914 have any blocks on disk beginning with JFS_MAGIC_NUMBER. */
915 jbd_debug(1, "JBD: Zeroing out journal blocks...\n");
916 for (i = 0; i < journal->j_maxlen; i++) {
917 err = journal_bmap(journal, i, &blocknr);
918 if (err)
919 return err;
920 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
921 lock_buffer(bh);
922 memset (bh->b_data, 0, journal->j_blocksize);
923 BUFFER_TRACE(bh, "marking dirty");
924 mark_buffer_dirty(bh);
925 BUFFER_TRACE(bh, "marking uptodate");
926 set_buffer_uptodate(bh);
927 unlock_buffer(bh);
928 __brelse(bh);
929 }
930
931 sync_blockdev(journal->j_dev);
932 jbd_debug(1, "JBD: journal cleared.\n");
933
934 /* OK, fill in the initial static fields in the new superblock */
935 sb = journal->j_superblock;
936
937 sb->s_header.h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
938 sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2);
939
940 sb->s_blocksize = cpu_to_be32(journal->j_blocksize);
941 sb->s_maxlen = cpu_to_be32(journal->j_maxlen);
942 sb->s_first = cpu_to_be32(1);
943
944 journal->j_transaction_sequence = 1;
945
946 journal->j_flags &= ~JFS_ABORT;
947 journal->j_format_version = 2;
948
949 return journal_reset(journal);
950}
951
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700952/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953 * void journal_update_superblock() - Update journal sb on disk.
954 * @journal: The journal to update.
955 * @wait: Set to '0' if you don't want to wait for IO completion.
956 *
957 * Update a journal's dynamic superblock fields and write it to disk,
958 * optionally waiting for the IO to complete.
959 */
960void journal_update_superblock(journal_t *journal, int wait)
961{
962 journal_superblock_t *sb = journal->j_superblock;
963 struct buffer_head *bh = journal->j_sb_buffer;
964
965 /*
966 * As a special case, if the on-disk copy is already marked as needing
967 * no recovery (s_start == 0) and there are no outstanding transactions
968 * in the filesystem, then we can safely defer the superblock update
969 * until the next commit by setting JFS_FLUSHED. This avoids
970 * attempting a write to a potential-readonly device.
971 */
972 if (sb->s_start == 0 && journal->j_tail_sequence ==
973 journal->j_transaction_sequence) {
974 jbd_debug(1,"JBD: Skipping superblock update on recovered sb "
Jan Kara9c28cbc2009-08-03 19:21:00 +0200975 "(start %u, seq %d, errno %d)\n",
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700976 journal->j_tail, journal->j_tail_sequence,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 journal->j_errno);
978 goto out;
979 }
980
981 spin_lock(&journal->j_state_lock);
Jan Kara9c28cbc2009-08-03 19:21:00 +0200982 jbd_debug(1,"JBD: updating superblock (start %u, seq %d, errno %d)\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983 journal->j_tail, journal->j_tail_sequence, journal->j_errno);
984
985 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
986 sb->s_start = cpu_to_be32(journal->j_tail);
987 sb->s_errno = cpu_to_be32(journal->j_errno);
988 spin_unlock(&journal->j_state_lock);
989
990 BUFFER_TRACE(bh, "marking dirty");
991 mark_buffer_dirty(bh);
992 if (wait)
993 sync_dirty_buffer(bh);
994 else
Jan Kara26707692005-09-06 15:19:12 -0700995 ll_rw_block(SWRITE, 1, &bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996
997out:
998 /* If we have just flushed the log (by marking s_start==0), then
999 * any future commit will have to be careful to update the
1000 * superblock again to re-record the true start of the log. */
1001
1002 spin_lock(&journal->j_state_lock);
1003 if (sb->s_start)
1004 journal->j_flags &= ~JFS_FLUSHED;
1005 else
1006 journal->j_flags |= JFS_FLUSHED;
1007 spin_unlock(&journal->j_state_lock);
1008}
1009
1010/*
1011 * Read the superblock for a given journal, performing initial
1012 * validation of the format.
1013 */
1014
1015static int journal_get_superblock(journal_t *journal)
1016{
1017 struct buffer_head *bh;
1018 journal_superblock_t *sb;
1019 int err = -EIO;
1020
1021 bh = journal->j_sb_buffer;
1022
1023 J_ASSERT(bh != NULL);
1024 if (!buffer_uptodate(bh)) {
1025 ll_rw_block(READ, 1, &bh);
1026 wait_on_buffer(bh);
1027 if (!buffer_uptodate(bh)) {
1028 printk (KERN_ERR
1029 "JBD: IO error reading journal superblock\n");
1030 goto out;
1031 }
1032 }
1033
1034 sb = journal->j_superblock;
1035
1036 err = -EINVAL;
1037
1038 if (sb->s_header.h_magic != cpu_to_be32(JFS_MAGIC_NUMBER) ||
1039 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1040 printk(KERN_WARNING "JBD: no valid journal superblock found\n");
1041 goto out;
1042 }
1043
1044 switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1045 case JFS_SUPERBLOCK_V1:
1046 journal->j_format_version = 1;
1047 break;
1048 case JFS_SUPERBLOCK_V2:
1049 journal->j_format_version = 2;
1050 break;
1051 default:
1052 printk(KERN_WARNING "JBD: unrecognised superblock format ID\n");
1053 goto out;
1054 }
1055
1056 if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
1057 journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
1058 else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
1059 printk (KERN_WARNING "JBD: journal file too short\n");
1060 goto out;
1061 }
1062
1063 return 0;
1064
1065out:
1066 journal_fail_superblock(journal);
1067 return err;
1068}
1069
1070/*
1071 * Load the on-disk journal superblock and read the key fields into the
1072 * journal_t.
1073 */
1074
1075static int load_superblock(journal_t *journal)
1076{
1077 int err;
1078 journal_superblock_t *sb;
1079
1080 err = journal_get_superblock(journal);
1081 if (err)
1082 return err;
1083
1084 sb = journal->j_superblock;
1085
1086 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1087 journal->j_tail = be32_to_cpu(sb->s_start);
1088 journal->j_first = be32_to_cpu(sb->s_first);
1089 journal->j_last = be32_to_cpu(sb->s_maxlen);
1090 journal->j_errno = be32_to_cpu(sb->s_errno);
1091
1092 return 0;
1093}
1094
1095
1096/**
1097 * int journal_load() - Read journal from disk.
1098 * @journal: Journal to act on.
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001099 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100 * Given a journal_t structure which tells us which disk blocks contain
1101 * a journal, read the journal from disk to initialise the in-memory
1102 * structures.
1103 */
1104int journal_load(journal_t *journal)
1105{
1106 int err;
Badari Pulavartyea817392006-08-27 01:23:52 -07001107 journal_superblock_t *sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108
1109 err = load_superblock(journal);
1110 if (err)
1111 return err;
1112
Badari Pulavartyea817392006-08-27 01:23:52 -07001113 sb = journal->j_superblock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001114 /* If this is a V2 superblock, then we have to check the
1115 * features flags on it. */
1116
1117 if (journal->j_format_version >= 2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118 if ((sb->s_feature_ro_compat &
1119 ~cpu_to_be32(JFS_KNOWN_ROCOMPAT_FEATURES)) ||
1120 (sb->s_feature_incompat &
1121 ~cpu_to_be32(JFS_KNOWN_INCOMPAT_FEATURES))) {
1122 printk (KERN_WARNING
1123 "JBD: Unrecognised features on journal\n");
1124 return -EINVAL;
1125 }
1126 }
1127
1128 /* Let the recovery code check whether it needs to recover any
1129 * data from the journal. */
1130 if (journal_recover(journal))
1131 goto recovery_error;
1132
1133 /* OK, we've finished with the dynamic journal bits:
1134 * reinitialise the dynamic contents of the superblock in memory
1135 * and reset them on disk. */
1136 if (journal_reset(journal))
1137 goto recovery_error;
1138
1139 journal->j_flags &= ~JFS_ABORT;
1140 journal->j_flags |= JFS_LOADED;
1141 return 0;
1142
1143recovery_error:
1144 printk (KERN_WARNING "JBD: recovery failed\n");
1145 return -EIO;
1146}
1147
1148/**
1149 * void journal_destroy() - Release a journal_t structure.
1150 * @journal: Journal to act on.
1151 *
1152 * Release a journal_t structure once it is no longer in use by the
1153 * journaled object.
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001154 * Return <0 if we couldn't clean up the journal.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 */
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001156int journal_destroy(journal_t *journal)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001157{
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001158 int err = 0;
1159
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160 /* Wait for the commit thread to wake up and die. */
1161 journal_kill_thread(journal);
1162
1163 /* Force a final log commit */
1164 if (journal->j_running_transaction)
1165 journal_commit_transaction(journal);
1166
1167 /* Force any old transactions to disk */
1168
1169 /* Totally anal locking here... */
1170 spin_lock(&journal->j_list_lock);
1171 while (journal->j_checkpoint_transactions != NULL) {
1172 spin_unlock(&journal->j_list_lock);
1173 log_do_checkpoint(journal);
1174 spin_lock(&journal->j_list_lock);
1175 }
1176
1177 J_ASSERT(journal->j_running_transaction == NULL);
1178 J_ASSERT(journal->j_committing_transaction == NULL);
1179 J_ASSERT(journal->j_checkpoint_transactions == NULL);
1180 spin_unlock(&journal->j_list_lock);
1181
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 if (journal->j_sb_buffer) {
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001183 if (!is_journal_aborted(journal)) {
1184 /* We can now mark the journal as empty. */
1185 journal->j_tail = 0;
1186 journal->j_tail_sequence =
1187 ++journal->j_transaction_sequence;
1188 journal_update_superblock(journal, 1);
1189 } else {
1190 err = -EIO;
1191 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192 brelse(journal->j_sb_buffer);
1193 }
1194
1195 if (journal->j_inode)
1196 iput(journal->j_inode);
1197 if (journal->j_revoke)
1198 journal_destroy_revoke(journal);
1199 kfree(journal->j_wbuf);
1200 kfree(journal);
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001201
1202 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203}
1204
1205
1206/**
1207 *int journal_check_used_features () - Check if features specified are used.
1208 * @journal: Journal to check.
1209 * @compat: bitmask of compatible features
1210 * @ro: bitmask of features that force read-only mount
1211 * @incompat: bitmask of incompatible features
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001212 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 * Check whether the journal uses all of a given set of
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001214 * features. Return true (non-zero) if it does.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 **/
1216
1217int journal_check_used_features (journal_t *journal, unsigned long compat,
1218 unsigned long ro, unsigned long incompat)
1219{
1220 journal_superblock_t *sb;
1221
1222 if (!compat && !ro && !incompat)
1223 return 1;
1224 if (journal->j_format_version == 1)
1225 return 0;
1226
1227 sb = journal->j_superblock;
1228
1229 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
1230 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
1231 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
1232 return 1;
1233
1234 return 0;
1235}
1236
1237/**
1238 * int journal_check_available_features() - Check feature set in journalling layer
1239 * @journal: Journal to check.
1240 * @compat: bitmask of compatible features
1241 * @ro: bitmask of features that force read-only mount
1242 * @incompat: bitmask of incompatible features
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001243 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244 * Check whether the journaling code supports the use of
1245 * all of a given set of features on this journal. Return true
1246 * (non-zero) if it can. */
1247
1248int journal_check_available_features (journal_t *journal, unsigned long compat,
1249 unsigned long ro, unsigned long incompat)
1250{
1251 journal_superblock_t *sb;
1252
1253 if (!compat && !ro && !incompat)
1254 return 1;
1255
1256 sb = journal->j_superblock;
1257
1258 /* We can support any known requested features iff the
1259 * superblock is in version 2. Otherwise we fail to support any
1260 * extended sb features. */
1261
1262 if (journal->j_format_version != 2)
1263 return 0;
1264
1265 if ((compat & JFS_KNOWN_COMPAT_FEATURES) == compat &&
1266 (ro & JFS_KNOWN_ROCOMPAT_FEATURES) == ro &&
1267 (incompat & JFS_KNOWN_INCOMPAT_FEATURES) == incompat)
1268 return 1;
1269
1270 return 0;
1271}
1272
1273/**
1274 * int journal_set_features () - Mark a given journal feature in the superblock
1275 * @journal: Journal to act on.
1276 * @compat: bitmask of compatible features
1277 * @ro: bitmask of features that force read-only mount
1278 * @incompat: bitmask of incompatible features
1279 *
1280 * Mark a given journal feature as present on the
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001281 * superblock. Returns true if the requested features could be set.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 *
1283 */
1284
1285int journal_set_features (journal_t *journal, unsigned long compat,
1286 unsigned long ro, unsigned long incompat)
1287{
1288 journal_superblock_t *sb;
1289
1290 if (journal_check_used_features(journal, compat, ro, incompat))
1291 return 1;
1292
1293 if (!journal_check_available_features(journal, compat, ro, incompat))
1294 return 0;
1295
1296 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1297 compat, ro, incompat);
1298
1299 sb = journal->j_superblock;
1300
1301 sb->s_feature_compat |= cpu_to_be32(compat);
1302 sb->s_feature_ro_compat |= cpu_to_be32(ro);
1303 sb->s_feature_incompat |= cpu_to_be32(incompat);
1304
1305 return 1;
1306}
1307
1308
1309/**
1310 * int journal_update_format () - Update on-disk journal structure.
1311 * @journal: Journal to act on.
1312 *
1313 * Given an initialised but unloaded journal struct, poke about in the
1314 * on-disk structure to update it to the most recent supported version.
1315 */
1316int journal_update_format (journal_t *journal)
1317{
1318 journal_superblock_t *sb;
1319 int err;
1320
1321 err = journal_get_superblock(journal);
1322 if (err)
1323 return err;
1324
1325 sb = journal->j_superblock;
1326
1327 switch (be32_to_cpu(sb->s_header.h_blocktype)) {
1328 case JFS_SUPERBLOCK_V2:
1329 return 0;
1330 case JFS_SUPERBLOCK_V1:
1331 return journal_convert_superblock_v1(journal, sb);
1332 default:
1333 break;
1334 }
1335 return -EINVAL;
1336}
1337
1338static int journal_convert_superblock_v1(journal_t *journal,
1339 journal_superblock_t *sb)
1340{
1341 int offset, blocksize;
1342 struct buffer_head *bh;
1343
1344 printk(KERN_WARNING
1345 "JBD: Converting superblock from version 1 to 2.\n");
1346
1347 /* Pre-initialise new fields to zero */
1348 offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
1349 blocksize = be32_to_cpu(sb->s_blocksize);
1350 memset(&sb->s_feature_compat, 0, blocksize-offset);
1351
1352 sb->s_nr_users = cpu_to_be32(1);
1353 sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2);
1354 journal->j_format_version = 2;
1355
1356 bh = journal->j_sb_buffer;
1357 BUFFER_TRACE(bh, "marking dirty");
1358 mark_buffer_dirty(bh);
1359 sync_dirty_buffer(bh);
1360 return 0;
1361}
1362
1363
1364/**
1365 * int journal_flush () - Flush journal
1366 * @journal: Journal to act on.
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001367 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 * Flush all data for a given journal to disk and empty the journal.
1369 * Filesystems can use this when remounting readonly to ensure that
1370 * recovery does not need to happen on remount.
1371 */
1372
1373int journal_flush(journal_t *journal)
1374{
1375 int err = 0;
1376 transaction_t *transaction = NULL;
Jan Kara9c28cbc2009-08-03 19:21:00 +02001377 unsigned int old_tail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001378
1379 spin_lock(&journal->j_state_lock);
1380
1381 /* Force everything buffered to the log... */
1382 if (journal->j_running_transaction) {
1383 transaction = journal->j_running_transaction;
1384 __log_start_commit(journal, transaction->t_tid);
1385 } else if (journal->j_committing_transaction)
1386 transaction = journal->j_committing_transaction;
1387
1388 /* Wait for the log commit to complete... */
1389 if (transaction) {
1390 tid_t tid = transaction->t_tid;
1391
1392 spin_unlock(&journal->j_state_lock);
1393 log_wait_commit(journal, tid);
1394 } else {
1395 spin_unlock(&journal->j_state_lock);
1396 }
1397
1398 /* ...and flush everything in the log out to disk. */
1399 spin_lock(&journal->j_list_lock);
1400 while (!err && journal->j_checkpoint_transactions != NULL) {
1401 spin_unlock(&journal->j_list_lock);
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001402 mutex_lock(&journal->j_checkpoint_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001403 err = log_do_checkpoint(journal);
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001404 mutex_unlock(&journal->j_checkpoint_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405 spin_lock(&journal->j_list_lock);
1406 }
1407 spin_unlock(&journal->j_list_lock);
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001408
1409 if (is_journal_aborted(journal))
1410 return -EIO;
1411
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 cleanup_journal_tail(journal);
1413
1414 /* Finally, mark the journal as really needing no recovery.
1415 * This sets s_start==0 in the underlying superblock, which is
1416 * the magic code for a fully-recovered superblock. Any future
1417 * commits of data to the journal will restore the current
1418 * s_start value. */
1419 spin_lock(&journal->j_state_lock);
1420 old_tail = journal->j_tail;
1421 journal->j_tail = 0;
1422 spin_unlock(&journal->j_state_lock);
1423 journal_update_superblock(journal, 1);
1424 spin_lock(&journal->j_state_lock);
1425 journal->j_tail = old_tail;
1426
1427 J_ASSERT(!journal->j_running_transaction);
1428 J_ASSERT(!journal->j_committing_transaction);
1429 J_ASSERT(!journal->j_checkpoint_transactions);
1430 J_ASSERT(journal->j_head == journal->j_tail);
1431 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
1432 spin_unlock(&journal->j_state_lock);
Hidehiro Kawai4afe9782008-10-22 14:15:00 -07001433 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001434}
1435
1436/**
1437 * int journal_wipe() - Wipe journal contents
1438 * @journal: Journal to act on.
1439 * @write: flag (see below)
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001440 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001441 * Wipe out all of the contents of a journal, safely. This will produce
1442 * a warning if the journal contains any valid recovery information.
1443 * Must be called between journal_init_*() and journal_load().
1444 *
1445 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
1446 * we merely suppress recovery.
1447 */
1448
1449int journal_wipe(journal_t *journal, int write)
1450{
1451 journal_superblock_t *sb;
1452 int err = 0;
1453
1454 J_ASSERT (!(journal->j_flags & JFS_LOADED));
1455
1456 err = load_superblock(journal);
1457 if (err)
1458 return err;
1459
1460 sb = journal->j_superblock;
1461
1462 if (!journal->j_tail)
1463 goto no_recovery;
1464
1465 printk (KERN_WARNING "JBD: %s recovery information on journal\n",
1466 write ? "Clearing" : "Ignoring");
1467
1468 err = journal_skip_recovery(journal);
1469 if (write)
1470 journal_update_superblock(journal, 1);
1471
1472 no_recovery:
1473 return err;
1474}
1475
1476/*
1477 * journal_dev_name: format a character string to describe on what
1478 * device this journal is present.
1479 */
1480
Adrian Bunk022a4a72005-09-06 15:16:41 -07001481static const char *journal_dev_name(journal_t *journal, char *buffer)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001482{
1483 struct block_device *bdev;
1484
1485 if (journal->j_inode)
1486 bdev = journal->j_inode->i_sb->s_bdev;
1487 else
1488 bdev = journal->j_dev;
1489
1490 return bdevname(bdev, buffer);
1491}
1492
1493/*
1494 * Journal abort has very specific semantics, which we describe
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001495 * for journal abort.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496 *
1497 * Two internal function, which provide abort to te jbd layer
1498 * itself are here.
1499 */
1500
1501/*
1502 * Quick version for internal journal use (doesn't lock the journal).
1503 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
1504 * and don't attempt to make any other journal updates.
1505 */
Adrian Bunk53308382008-02-06 01:40:12 -08001506static void __journal_abort_hard(journal_t *journal)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507{
1508 transaction_t *transaction;
1509 char b[BDEVNAME_SIZE];
1510
1511 if (journal->j_flags & JFS_ABORT)
1512 return;
1513
1514 printk(KERN_ERR "Aborting journal on device %s.\n",
1515 journal_dev_name(journal, b));
1516
1517 spin_lock(&journal->j_state_lock);
1518 journal->j_flags |= JFS_ABORT;
1519 transaction = journal->j_running_transaction;
1520 if (transaction)
1521 __log_start_commit(journal, transaction->t_tid);
1522 spin_unlock(&journal->j_state_lock);
1523}
1524
1525/* Soft abort: record the abort error status in the journal superblock,
1526 * but don't do any other IO. */
Adrian Bunk022a4a72005-09-06 15:16:41 -07001527static void __journal_abort_soft (journal_t *journal, int errno)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001528{
1529 if (journal->j_flags & JFS_ABORT)
1530 return;
1531
1532 if (!journal->j_errno)
1533 journal->j_errno = errno;
1534
1535 __journal_abort_hard(journal);
1536
1537 if (errno)
1538 journal_update_superblock(journal, 1);
1539}
1540
1541/**
1542 * void journal_abort () - Shutdown the journal immediately.
1543 * @journal: the journal to shutdown.
1544 * @errno: an error number to record in the journal indicating
1545 * the reason for the shutdown.
1546 *
1547 * Perform a complete, immediate shutdown of the ENTIRE
1548 * journal (not of a single transaction). This operation cannot be
1549 * undone without closing and reopening the journal.
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001550 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001551 * The journal_abort function is intended to support higher level error
1552 * recovery mechanisms such as the ext2/ext3 remount-readonly error
1553 * mode.
1554 *
1555 * Journal abort has very specific semantics. Any existing dirty,
1556 * unjournaled buffers in the main filesystem will still be written to
1557 * disk by bdflush, but the journaling mechanism will be suspended
1558 * immediately and no further transaction commits will be honoured.
1559 *
1560 * Any dirty, journaled buffers will be written back to disk without
1561 * hitting the journal. Atomicity cannot be guaranteed on an aborted
1562 * filesystem, but we _do_ attempt to leave as much data as possible
1563 * behind for fsck to use for cleanup.
1564 *
1565 * Any attempt to get a new transaction handle on a journal which is in
1566 * ABORT state will just result in an -EROFS error return. A
1567 * journal_stop on an existing handle will return -EIO if we have
1568 * entered abort state during the update.
1569 *
1570 * Recursive transactions are not disturbed by journal abort until the
1571 * final journal_stop, which will receive the -EIO error.
1572 *
1573 * Finally, the journal_abort call allows the caller to supply an errno
1574 * which will be recorded (if possible) in the journal superblock. This
1575 * allows a client to record failure conditions in the middle of a
1576 * transaction without having to complete the transaction to record the
1577 * failure to disk. ext3_error, for example, now uses this
1578 * functionality.
1579 *
1580 * Errors which originate from within the journaling layer will NOT
1581 * supply an errno; a null errno implies that absolutely no further
1582 * writes are done to the journal (unless there are any already in
1583 * progress).
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001584 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001585 */
1586
1587void journal_abort(journal_t *journal, int errno)
1588{
1589 __journal_abort_soft(journal, errno);
1590}
1591
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001592/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001593 * int journal_errno () - returns the journal's error state.
1594 * @journal: journal to examine.
1595 *
1596 * This is the errno numbet set with journal_abort(), the last
1597 * time the journal was mounted - if the journal was stopped
1598 * without calling abort this will be 0.
1599 *
1600 * If the journal has been aborted on this mount time -EROFS will
1601 * be returned.
1602 */
1603int journal_errno(journal_t *journal)
1604{
1605 int err;
1606
1607 spin_lock(&journal->j_state_lock);
1608 if (journal->j_flags & JFS_ABORT)
1609 err = -EROFS;
1610 else
1611 err = journal->j_errno;
1612 spin_unlock(&journal->j_state_lock);
1613 return err;
1614}
1615
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001616/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001617 * int journal_clear_err () - clears the journal's error state
1618 * @journal: journal to act on.
1619 *
1620 * An error must be cleared or Acked to take a FS out of readonly
1621 * mode.
1622 */
1623int journal_clear_err(journal_t *journal)
1624{
1625 int err = 0;
1626
1627 spin_lock(&journal->j_state_lock);
1628 if (journal->j_flags & JFS_ABORT)
1629 err = -EROFS;
1630 else
1631 journal->j_errno = 0;
1632 spin_unlock(&journal->j_state_lock);
1633 return err;
1634}
1635
Mingming Caoae6ddcc2006-09-27 01:49:27 -07001636/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001637 * void journal_ack_err() - Ack journal err.
1638 * @journal: journal to act on.
1639 *
1640 * An error must be cleared or Acked to take a FS out of readonly
1641 * mode.
1642 */
1643void journal_ack_err(journal_t *journal)
1644{
1645 spin_lock(&journal->j_state_lock);
1646 if (journal->j_errno)
1647 journal->j_flags |= JFS_ACK_ERR;
1648 spin_unlock(&journal->j_state_lock);
1649}
1650
1651int journal_blocks_per_page(struct inode *inode)
1652{
1653 return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
1654}
1655
1656/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001657 * Journal_head storage management
1658 */
Christoph Lametere18b8902006-12-06 20:33:20 -08001659static struct kmem_cache *journal_head_cache;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001660#ifdef CONFIG_JBD_DEBUG
1661static atomic_t nr_journal_heads = ATOMIC_INIT(0);
1662#endif
1663
1664static int journal_init_journal_head_cache(void)
1665{
1666 int retval;
1667
Al Viro1076d172008-03-29 03:07:18 +00001668 J_ASSERT(journal_head_cache == NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669 journal_head_cache = kmem_cache_create("journal_head",
1670 sizeof(struct journal_head),
1671 0, /* offset */
Mel Gormane12ba742007-10-16 01:25:52 -07001672 SLAB_TEMPORARY, /* flags */
Paul Mundt20c2df82007-07-20 10:11:58 +09001673 NULL); /* ctor */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001674 retval = 0;
Al Viro1076d172008-03-29 03:07:18 +00001675 if (!journal_head_cache) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001676 retval = -ENOMEM;
1677 printk(KERN_EMERG "JBD: no memory for journal_head cache\n");
1678 }
1679 return retval;
1680}
1681
1682static void journal_destroy_journal_head_cache(void)
1683{
Duane Griffin3850f7a2008-07-25 01:46:19 -07001684 if (journal_head_cache) {
1685 kmem_cache_destroy(journal_head_cache);
1686 journal_head_cache = NULL;
1687 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001688}
1689
1690/*
1691 * journal_head splicing and dicing
1692 */
1693static struct journal_head *journal_alloc_journal_head(void)
1694{
1695 struct journal_head *ret;
1696 static unsigned long last_warning;
1697
1698#ifdef CONFIG_JBD_DEBUG
1699 atomic_inc(&nr_journal_heads);
1700#endif
1701 ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS);
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001702 if (ret == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001703 jbd_debug(1, "out of memory for journal_head\n");
1704 if (time_after(jiffies, last_warning + 5*HZ)) {
1705 printk(KERN_NOTICE "ENOMEM in %s, retrying.\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -07001706 __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001707 last_warning = jiffies;
1708 }
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001709 while (ret == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001710 yield();
1711 ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS);
1712 }
1713 }
1714 return ret;
1715}
1716
1717static void journal_free_journal_head(struct journal_head *jh)
1718{
1719#ifdef CONFIG_JBD_DEBUG
1720 atomic_dec(&nr_journal_heads);
Randy Dunlapc9cf5522006-06-27 02:53:52 -07001721 memset(jh, JBD_POISON_FREE, sizeof(*jh));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722#endif
1723 kmem_cache_free(journal_head_cache, jh);
1724}
1725
1726/*
1727 * A journal_head is attached to a buffer_head whenever JBD has an
1728 * interest in the buffer.
1729 *
1730 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
1731 * is set. This bit is tested in core kernel code where we need to take
1732 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
1733 * there.
1734 *
1735 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
1736 *
1737 * When a buffer has its BH_JBD bit set it is immune from being released by
1738 * core kernel code, mainly via ->b_count.
1739 *
1740 * A journal_head may be detached from its buffer_head when the journal_head's
1741 * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL.
1742 * Various places in JBD call journal_remove_journal_head() to indicate that the
1743 * journal_head can be dropped if needed.
1744 *
1745 * Various places in the kernel want to attach a journal_head to a buffer_head
1746 * _before_ attaching the journal_head to a transaction. To protect the
1747 * journal_head in this situation, journal_add_journal_head elevates the
1748 * journal_head's b_jcount refcount by one. The caller must call
1749 * journal_put_journal_head() to undo this.
1750 *
1751 * So the typical usage would be:
1752 *
1753 * (Attach a journal_head if needed. Increments b_jcount)
1754 * struct journal_head *jh = journal_add_journal_head(bh);
1755 * ...
1756 * jh->b_transaction = xxx;
1757 * journal_put_journal_head(jh);
1758 *
1759 * Now, the journal_head's b_jcount is zero, but it is safe from being released
1760 * because it has a non-zero b_transaction.
1761 */
1762
1763/*
1764 * Give a buffer_head a journal_head.
1765 *
1766 * Doesn't need the journal lock.
1767 * May sleep.
1768 */
1769struct journal_head *journal_add_journal_head(struct buffer_head *bh)
1770{
1771 struct journal_head *jh;
1772 struct journal_head *new_jh = NULL;
1773
1774repeat:
1775 if (!buffer_jbd(bh)) {
1776 new_jh = journal_alloc_journal_head();
1777 memset(new_jh, 0, sizeof(*new_jh));
1778 }
1779
1780 jbd_lock_bh_journal_head(bh);
1781 if (buffer_jbd(bh)) {
1782 jh = bh2jh(bh);
1783 } else {
1784 J_ASSERT_BH(bh,
1785 (atomic_read(&bh->b_count) > 0) ||
1786 (bh->b_page && bh->b_page->mapping));
1787
1788 if (!new_jh) {
1789 jbd_unlock_bh_journal_head(bh);
1790 goto repeat;
1791 }
1792
1793 jh = new_jh;
1794 new_jh = NULL; /* We consumed it */
1795 set_buffer_jbd(bh);
1796 bh->b_private = jh;
1797 jh->b_bh = bh;
1798 get_bh(bh);
1799 BUFFER_TRACE(bh, "added journal_head");
1800 }
1801 jh->b_jcount++;
1802 jbd_unlock_bh_journal_head(bh);
1803 if (new_jh)
1804 journal_free_journal_head(new_jh);
1805 return bh->b_private;
1806}
1807
1808/*
1809 * Grab a ref against this buffer_head's journal_head. If it ended up not
1810 * having a journal_head, return NULL
1811 */
1812struct journal_head *journal_grab_journal_head(struct buffer_head *bh)
1813{
1814 struct journal_head *jh = NULL;
1815
1816 jbd_lock_bh_journal_head(bh);
1817 if (buffer_jbd(bh)) {
1818 jh = bh2jh(bh);
1819 jh->b_jcount++;
1820 }
1821 jbd_unlock_bh_journal_head(bh);
1822 return jh;
1823}
1824
1825static void __journal_remove_journal_head(struct buffer_head *bh)
1826{
1827 struct journal_head *jh = bh2jh(bh);
1828
1829 J_ASSERT_JH(jh, jh->b_jcount >= 0);
1830
1831 get_bh(bh);
1832 if (jh->b_jcount == 0) {
1833 if (jh->b_transaction == NULL &&
1834 jh->b_next_transaction == NULL &&
1835 jh->b_cp_transaction == NULL) {
1836 J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
1837 J_ASSERT_BH(bh, buffer_jbd(bh));
1838 J_ASSERT_BH(bh, jh2bh(jh) == bh);
1839 BUFFER_TRACE(bh, "remove journal_head");
1840 if (jh->b_frozen_data) {
1841 printk(KERN_WARNING "%s: freeing "
1842 "b_frozen_data\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -07001843 __func__);
Mingming Caoc089d492007-10-16 18:38:25 -04001844 jbd_free(jh->b_frozen_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845 }
1846 if (jh->b_committed_data) {
1847 printk(KERN_WARNING "%s: freeing "
1848 "b_committed_data\n",
Harvey Harrison08fc99b2008-04-28 02:16:16 -07001849 __func__);
Mingming Caoc089d492007-10-16 18:38:25 -04001850 jbd_free(jh->b_committed_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851 }
1852 bh->b_private = NULL;
1853 jh->b_bh = NULL; /* debug, really */
1854 clear_buffer_jbd(bh);
1855 __brelse(bh);
1856 journal_free_journal_head(jh);
1857 } else {
1858 BUFFER_TRACE(bh, "journal_head was locked");
1859 }
1860 }
1861}
1862
1863/*
1864 * journal_remove_journal_head(): if the buffer isn't attached to a transaction
1865 * and has a zero b_jcount then remove and release its journal_head. If we did
1866 * see that the buffer is not used by any transaction we also "logically"
1867 * decrement ->b_count.
1868 *
1869 * We in fact take an additional increment on ->b_count as a convenience,
1870 * because the caller usually wants to do additional things with the bh
1871 * after calling here.
1872 * The caller of journal_remove_journal_head() *must* run __brelse(bh) at some
1873 * time. Once the caller has run __brelse(), the buffer is eligible for
1874 * reaping by try_to_free_buffers().
1875 */
1876void journal_remove_journal_head(struct buffer_head *bh)
1877{
1878 jbd_lock_bh_journal_head(bh);
1879 __journal_remove_journal_head(bh);
1880 jbd_unlock_bh_journal_head(bh);
1881}
1882
1883/*
1884 * Drop a reference on the passed journal_head. If it fell to zero then try to
1885 * release the journal_head from the buffer_head.
1886 */
1887void journal_put_journal_head(struct journal_head *jh)
1888{
1889 struct buffer_head *bh = jh2bh(jh);
1890
1891 jbd_lock_bh_journal_head(bh);
1892 J_ASSERT_JH(jh, jh->b_jcount > 0);
1893 --jh->b_jcount;
1894 if (!jh->b_jcount && !jh->b_transaction) {
1895 __journal_remove_journal_head(bh);
1896 __brelse(bh);
1897 }
1898 jbd_unlock_bh_journal_head(bh);
1899}
1900
1901/*
Jose R. Santosc2a91592007-10-18 23:39:22 -07001902 * debugfs tunables
Linus Torvalds1da177e2005-04-16 15:20:36 -07001903 */
Jose R. Santosc2a91592007-10-18 23:39:22 -07001904#ifdef CONFIG_JBD_DEBUG
1905
1906u8 journal_enable_debug __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001907EXPORT_SYMBOL(journal_enable_debug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908
Jose R. Santosc2a91592007-10-18 23:39:22 -07001909static struct dentry *jbd_debugfs_dir;
1910static struct dentry *jbd_debug;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911
Jose R. Santosc2a91592007-10-18 23:39:22 -07001912static void __init jbd_create_debugfs_entry(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001913{
Jose R. Santosc2a91592007-10-18 23:39:22 -07001914 jbd_debugfs_dir = debugfs_create_dir("jbd", NULL);
1915 if (jbd_debugfs_dir)
Yin Kangkai765f8362009-12-15 14:48:25 -08001916 jbd_debug = debugfs_create_u8("jbd-debug", S_IRUGO | S_IWUSR,
Jose R. Santosc2a91592007-10-18 23:39:22 -07001917 jbd_debugfs_dir,
1918 &journal_enable_debug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001919}
1920
Jose R. Santosc2a91592007-10-18 23:39:22 -07001921static void __exit jbd_remove_debugfs_entry(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922{
Jose R. Santosc2a91592007-10-18 23:39:22 -07001923 debugfs_remove(jbd_debug);
1924 debugfs_remove(jbd_debugfs_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001925}
1926
1927#else
1928
Jose R. Santosc2a91592007-10-18 23:39:22 -07001929static inline void jbd_create_debugfs_entry(void)
1930{
1931}
1932
1933static inline void jbd_remove_debugfs_entry(void)
1934{
1935}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001936
1937#endif
1938
Christoph Lametere18b8902006-12-06 20:33:20 -08001939struct kmem_cache *jbd_handle_cache;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940
1941static int __init journal_init_handle_cache(void)
1942{
1943 jbd_handle_cache = kmem_cache_create("journal_handle",
1944 sizeof(handle_t),
1945 0, /* offset */
Mel Gormane12ba742007-10-16 01:25:52 -07001946 SLAB_TEMPORARY, /* flags */
Paul Mundt20c2df82007-07-20 10:11:58 +09001947 NULL); /* ctor */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001948 if (jbd_handle_cache == NULL) {
1949 printk(KERN_EMERG "JBD: failed to create handle cache\n");
1950 return -ENOMEM;
1951 }
1952 return 0;
1953}
1954
1955static void journal_destroy_handle_cache(void)
1956{
1957 if (jbd_handle_cache)
1958 kmem_cache_destroy(jbd_handle_cache);
1959}
1960
1961/*
1962 * Module startup and shutdown
1963 */
1964
1965static int __init journal_init_caches(void)
1966{
1967 int ret;
1968
1969 ret = journal_init_revoke_caches();
1970 if (ret == 0)
1971 ret = journal_init_journal_head_cache();
1972 if (ret == 0)
1973 ret = journal_init_handle_cache();
1974 return ret;
1975}
1976
1977static void journal_destroy_caches(void)
1978{
1979 journal_destroy_revoke_caches();
1980 journal_destroy_journal_head_cache();
1981 journal_destroy_handle_cache();
1982}
1983
1984static int __init journal_init(void)
1985{
1986 int ret;
1987
Alexey Dobriyan2aed3482006-09-27 01:49:28 -07001988 BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
Adrian Bunk022a4a72005-09-06 15:16:41 -07001989
Linus Torvalds1da177e2005-04-16 15:20:36 -07001990 ret = journal_init_caches();
1991 if (ret != 0)
1992 journal_destroy_caches();
Jose R. Santosc2a91592007-10-18 23:39:22 -07001993 jbd_create_debugfs_entry();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994 return ret;
1995}
1996
1997static void __exit journal_exit(void)
1998{
1999#ifdef CONFIG_JBD_DEBUG
2000 int n = atomic_read(&nr_journal_heads);
2001 if (n)
2002 printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n);
2003#endif
Jose R. Santosc2a91592007-10-18 23:39:22 -07002004 jbd_remove_debugfs_entry();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002005 journal_destroy_caches();
2006}
2007
2008MODULE_LICENSE("GPL");
2009module_init(journal_init);
2010module_exit(journal_exit);
2011