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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/journal.c
3 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 *
6 * Copyright 1998 Red Hat corp --- All Rights Reserved
7 *
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
11 *
12 * 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>
31#include <linux/smp_lock.h>
32#include <linux/init.h>
33#include <linux/mm.h>
34#include <linux/suspend.h>
35#include <linux/pagemap.h>
36#include <asm/uaccess.h>
37#include <asm/page.h>
38#include <linux/proc_fs.h>
39
40EXPORT_SYMBOL(journal_start);
41EXPORT_SYMBOL(journal_restart);
42EXPORT_SYMBOL(journal_extend);
43EXPORT_SYMBOL(journal_stop);
44EXPORT_SYMBOL(journal_lock_updates);
45EXPORT_SYMBOL(journal_unlock_updates);
46EXPORT_SYMBOL(journal_get_write_access);
47EXPORT_SYMBOL(journal_get_create_access);
48EXPORT_SYMBOL(journal_get_undo_access);
49EXPORT_SYMBOL(journal_dirty_data);
50EXPORT_SYMBOL(journal_dirty_metadata);
51EXPORT_SYMBOL(journal_release_buffer);
52EXPORT_SYMBOL(journal_forget);
53#if 0
54EXPORT_SYMBOL(journal_sync_buffer);
55#endif
56EXPORT_SYMBOL(journal_flush);
57EXPORT_SYMBOL(journal_revoke);
58
59EXPORT_SYMBOL(journal_init_dev);
60EXPORT_SYMBOL(journal_init_inode);
61EXPORT_SYMBOL(journal_update_format);
62EXPORT_SYMBOL(journal_check_used_features);
63EXPORT_SYMBOL(journal_check_available_features);
64EXPORT_SYMBOL(journal_set_features);
65EXPORT_SYMBOL(journal_create);
66EXPORT_SYMBOL(journal_load);
67EXPORT_SYMBOL(journal_destroy);
Linus Torvalds1da177e2005-04-16 15:20:36 -070068EXPORT_SYMBOL(journal_update_superblock);
69EXPORT_SYMBOL(journal_abort);
70EXPORT_SYMBOL(journal_errno);
71EXPORT_SYMBOL(journal_ack_err);
72EXPORT_SYMBOL(journal_clear_err);
73EXPORT_SYMBOL(log_wait_commit);
74EXPORT_SYMBOL(journal_start_commit);
75EXPORT_SYMBOL(journal_force_commit_nested);
76EXPORT_SYMBOL(journal_wipe);
77EXPORT_SYMBOL(journal_blocks_per_page);
78EXPORT_SYMBOL(journal_invalidatepage);
79EXPORT_SYMBOL(journal_try_to_free_buffers);
80EXPORT_SYMBOL(journal_force_commit);
81
82static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
Adrian Bunk022a4a72005-09-06 15:16:41 -070083static void __journal_abort_soft (journal_t *journal, int errno);
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
85/*
86 * Helper function used to manage commit timeouts
87 */
88
89static void commit_timeout(unsigned long __data)
90{
91 struct task_struct * p = (struct task_struct *) __data;
92
93 wake_up_process(p);
94}
95
Linus Torvalds1da177e2005-04-16 15:20:36 -070096/*
97 * kjournald: The main thread function used to manage a logging device
98 * journal.
99 *
100 * This kernel thread is responsible for two things:
101 *
102 * 1) COMMIT: Every so often we need to commit the current state of the
103 * filesystem to disk. The journal thread is responsible for writing
104 * all of the metadata buffers to disk.
105 *
106 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
107 * of the data in that part of the log has been rewritten elsewhere on
108 * the disk. Flushing these old buffers to reclaim space in the log is
109 * known as checkpointing, and this thread is responsible for that job.
110 */
111
Adrian Bunk022a4a72005-09-06 15:16:41 -0700112static int kjournald(void *arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113{
114 journal_t *journal = (journal_t *) arg;
115 transaction_t *transaction;
116 struct timer_list timer;
117
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 daemonize("kjournald");
119
120 /* Set up an interval timer which can be used to trigger a
121 commit wakeup after the commit interval expires */
122 init_timer(&timer);
123 timer.data = (unsigned long) current;
124 timer.function = commit_timeout;
125 journal->j_commit_timer = &timer;
126
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);
149 del_timer_sync(journal->j_commit_timer);
150 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)
183 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);
206 del_timer_sync(journal->j_commit_timer);
207 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
213static void journal_start_thread(journal_t *journal)
214{
215 kernel_thread(kjournald, journal, CLONE_VM|CLONE_FS|CLONE_FILES);
216 wait_event(journal->j_wait_done_commit, journal->j_task != 0);
217}
218
219static void journal_kill_thread(journal_t *journal)
220{
221 spin_lock(&journal->j_state_lock);
222 journal->j_flags |= JFS_UNMOUNT;
223
224 while (journal->j_task) {
225 wake_up(&journal->j_wait_commit);
226 spin_unlock(&journal->j_state_lock);
227 wait_event(journal->j_wait_done_commit, journal->j_task == 0);
228 spin_lock(&journal->j_state_lock);
229 }
230 spin_unlock(&journal->j_state_lock);
231}
232
233/*
234 * journal_write_metadata_buffer: write a metadata buffer to the journal.
235 *
236 * Writes a metadata buffer to a given disk block. The actual IO is not
237 * performed but a new buffer_head is constructed which labels the data
238 * to be written with the correct destination disk block.
239 *
240 * Any magic-number escaping which needs to be done will cause a
241 * copy-out here. If the buffer happens to start with the
242 * JFS_MAGIC_NUMBER, then we can't write it to the log directly: the
243 * magic number is only written to the log for descripter blocks. In
244 * this case, we copy the data and replace the first word with 0, and we
245 * return a result code which indicates that this buffer needs to be
246 * marked as an escaped buffer in the corresponding log descriptor
247 * block. The missing word can then be restored when the block is read
248 * during recovery.
249 *
250 * If the source buffer has already been modified by a new transaction
251 * since we took the last commit snapshot, we use the frozen copy of
252 * that data for IO. If we end up using the existing buffer_head's data
253 * for the write, then we *have* to lock the buffer to prevent anyone
254 * else from using and possibly modifying it while the IO is in
255 * progress.
256 *
257 * The function returns a pointer to the buffer_heads to be used for IO.
258 *
259 * We assume that the journal has already been locked in this function.
260 *
261 * Return value:
262 * <0: Error
263 * >=0: Finished OK
264 *
265 * On success:
266 * Bit 0 set == escape performed on the data
267 * Bit 1 set == buffer copy-out performed (kfree the data after IO)
268 */
269
270int journal_write_metadata_buffer(transaction_t *transaction,
271 struct journal_head *jh_in,
272 struct journal_head **jh_out,
273 int blocknr)
274{
275 int need_copy_out = 0;
276 int done_copy_out = 0;
277 int do_escape = 0;
278 char *mapped_data;
279 struct buffer_head *new_bh;
280 struct journal_head *new_jh;
281 struct page *new_page;
282 unsigned int new_offset;
283 struct buffer_head *bh_in = jh2bh(jh_in);
284
285 /*
286 * The buffer really shouldn't be locked: only the current committing
287 * transaction is allowed to write it, so nobody else is allowed
288 * to do any IO.
289 *
290 * akpm: except if we're journalling data, and write() output is
291 * also part of a shared mapping, and another thread has
292 * decided to launch a writepage() against this buffer.
293 */
294 J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
295
296 new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
297
298 /*
299 * If a new transaction has already done a buffer copy-out, then
300 * we use that version of the data for the commit.
301 */
302 jbd_lock_bh_state(bh_in);
303repeat:
304 if (jh_in->b_frozen_data) {
305 done_copy_out = 1;
306 new_page = virt_to_page(jh_in->b_frozen_data);
307 new_offset = offset_in_page(jh_in->b_frozen_data);
308 } else {
309 new_page = jh2bh(jh_in)->b_page;
310 new_offset = offset_in_page(jh2bh(jh_in)->b_data);
311 }
312
313 mapped_data = kmap_atomic(new_page, KM_USER0);
314 /*
315 * Check for escaping
316 */
317 if (*((__be32 *)(mapped_data + new_offset)) ==
318 cpu_to_be32(JFS_MAGIC_NUMBER)) {
319 need_copy_out = 1;
320 do_escape = 1;
321 }
322 kunmap_atomic(mapped_data, KM_USER0);
323
324 /*
325 * Do we need to do a data copy?
326 */
327 if (need_copy_out && !done_copy_out) {
328 char *tmp;
329
330 jbd_unlock_bh_state(bh_in);
331 tmp = jbd_rep_kmalloc(bh_in->b_size, GFP_NOFS);
332 jbd_lock_bh_state(bh_in);
333 if (jh_in->b_frozen_data) {
334 kfree(tmp);
335 goto repeat;
336 }
337
338 jh_in->b_frozen_data = tmp;
339 mapped_data = kmap_atomic(new_page, KM_USER0);
340 memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size);
341 kunmap_atomic(mapped_data, KM_USER0);
342
343 new_page = virt_to_page(tmp);
344 new_offset = offset_in_page(tmp);
345 done_copy_out = 1;
346 }
347
348 /*
349 * Did we need to do an escaping? Now we've done all the
350 * copying, we can finally do so.
351 */
352 if (do_escape) {
353 mapped_data = kmap_atomic(new_page, KM_USER0);
354 *((unsigned int *)(mapped_data + new_offset)) = 0;
355 kunmap_atomic(mapped_data, KM_USER0);
356 }
357
358 /* keep subsequent assertions sane */
359 new_bh->b_state = 0;
360 init_buffer(new_bh, NULL, NULL);
361 atomic_set(&new_bh->b_count, 1);
362 jbd_unlock_bh_state(bh_in);
363
364 new_jh = journal_add_journal_head(new_bh); /* This sleeps */
365
366 set_bh_page(new_bh, new_page, new_offset);
367 new_jh->b_transaction = NULL;
368 new_bh->b_size = jh2bh(jh_in)->b_size;
369 new_bh->b_bdev = transaction->t_journal->j_dev;
370 new_bh->b_blocknr = blocknr;
371 set_buffer_mapped(new_bh);
372 set_buffer_dirty(new_bh);
373
374 *jh_out = new_jh;
375
376 /*
377 * The to-be-written buffer needs to get moved to the io queue,
378 * and the original buffer whose contents we are shadowing or
379 * copying is moved to the transaction's shadow queue.
380 */
381 JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
382 journal_file_buffer(jh_in, transaction, BJ_Shadow);
383 JBUFFER_TRACE(new_jh, "file as BJ_IO");
384 journal_file_buffer(new_jh, transaction, BJ_IO);
385
386 return do_escape | (done_copy_out << 1);
387}
388
389/*
390 * Allocation code for the journal file. Manage the space left in the
391 * journal, so that we can begin checkpointing when appropriate.
392 */
393
394/*
395 * __log_space_left: Return the number of free blocks left in the journal.
396 *
397 * Called with the journal already locked.
398 *
399 * Called under j_state_lock
400 */
401
402int __log_space_left(journal_t *journal)
403{
404 int left = journal->j_free;
405
406 assert_spin_locked(&journal->j_state_lock);
407
408 /*
409 * Be pessimistic here about the number of those free blocks which
410 * might be required for log descriptor control blocks.
411 */
412
413#define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */
414
415 left -= MIN_LOG_RESERVED_BLOCKS;
416
417 if (left <= 0)
418 return 0;
419 left -= (left >> 3);
420 return left;
421}
422
423/*
424 * Called under j_state_lock. Returns true if a transaction was started.
425 */
426int __log_start_commit(journal_t *journal, tid_t target)
427{
428 /*
429 * Are we already doing a recent enough commit?
430 */
431 if (!tid_geq(journal->j_commit_request, target)) {
432 /*
433 * We want a new commit: OK, mark the request and wakup the
434 * commit thread. We do _not_ do the commit ourselves.
435 */
436
437 journal->j_commit_request = target;
438 jbd_debug(1, "JBD: requesting commit %d/%d\n",
439 journal->j_commit_request,
440 journal->j_commit_sequence);
441 wake_up(&journal->j_wait_commit);
442 return 1;
443 }
444 return 0;
445}
446
447int log_start_commit(journal_t *journal, tid_t tid)
448{
449 int ret;
450
451 spin_lock(&journal->j_state_lock);
452 ret = __log_start_commit(journal, tid);
453 spin_unlock(&journal->j_state_lock);
454 return ret;
455}
456
457/*
458 * Force and wait upon a commit if the calling process is not within
459 * transaction. This is used for forcing out undo-protected data which contains
460 * bitmaps, when the fs is running out of space.
461 *
462 * We can only force the running transaction if we don't have an active handle;
463 * otherwise, we will deadlock.
464 *
465 * Returns true if a transaction was started.
466 */
467int journal_force_commit_nested(journal_t *journal)
468{
469 transaction_t *transaction = NULL;
470 tid_t tid;
471
472 spin_lock(&journal->j_state_lock);
473 if (journal->j_running_transaction && !current->journal_info) {
474 transaction = journal->j_running_transaction;
475 __log_start_commit(journal, transaction->t_tid);
476 } else if (journal->j_committing_transaction)
477 transaction = journal->j_committing_transaction;
478
479 if (!transaction) {
480 spin_unlock(&journal->j_state_lock);
481 return 0; /* Nothing to retry */
482 }
483
484 tid = transaction->t_tid;
485 spin_unlock(&journal->j_state_lock);
486 log_wait_commit(journal, tid);
487 return 1;
488}
489
490/*
491 * Start a commit of the current running transaction (if any). Returns true
492 * if a transaction was started, and fills its tid in at *ptid
493 */
494int journal_start_commit(journal_t *journal, tid_t *ptid)
495{
496 int ret = 0;
497
498 spin_lock(&journal->j_state_lock);
499 if (journal->j_running_transaction) {
500 tid_t tid = journal->j_running_transaction->t_tid;
501
502 ret = __log_start_commit(journal, tid);
503 if (ret && ptid)
504 *ptid = tid;
505 } else if (journal->j_committing_transaction && ptid) {
506 /*
507 * If ext3_write_super() recently started a commit, then we
508 * have to wait for completion of that transaction
509 */
510 *ptid = journal->j_committing_transaction->t_tid;
511 ret = 1;
512 }
513 spin_unlock(&journal->j_state_lock);
514 return ret;
515}
516
517/*
518 * Wait for a specified commit to complete.
519 * The caller may not hold the journal lock.
520 */
521int log_wait_commit(journal_t *journal, tid_t tid)
522{
523 int err = 0;
524
525#ifdef CONFIG_JBD_DEBUG
526 spin_lock(&journal->j_state_lock);
527 if (!tid_geq(journal->j_commit_request, tid)) {
528 printk(KERN_EMERG
529 "%s: error: j_commit_request=%d, tid=%d\n",
530 __FUNCTION__, journal->j_commit_request, tid);
531 }
532 spin_unlock(&journal->j_state_lock);
533#endif
534 spin_lock(&journal->j_state_lock);
535 while (tid_gt(tid, journal->j_commit_sequence)) {
536 jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n",
537 tid, journal->j_commit_sequence);
538 wake_up(&journal->j_wait_commit);
539 spin_unlock(&journal->j_state_lock);
540 wait_event(journal->j_wait_done_commit,
541 !tid_gt(tid, journal->j_commit_sequence));
542 spin_lock(&journal->j_state_lock);
543 }
544 spin_unlock(&journal->j_state_lock);
545
546 if (unlikely(is_journal_aborted(journal))) {
547 printk(KERN_EMERG "journal commit I/O error\n");
548 err = -EIO;
549 }
550 return err;
551}
552
553/*
554 * Log buffer allocation routines:
555 */
556
557int journal_next_log_block(journal_t *journal, unsigned long *retp)
558{
559 unsigned long blocknr;
560
561 spin_lock(&journal->j_state_lock);
562 J_ASSERT(journal->j_free > 1);
563
564 blocknr = journal->j_head;
565 journal->j_head++;
566 journal->j_free--;
567 if (journal->j_head == journal->j_last)
568 journal->j_head = journal->j_first;
569 spin_unlock(&journal->j_state_lock);
570 return journal_bmap(journal, blocknr, retp);
571}
572
573/*
574 * Conversion of logical to physical block numbers for the journal
575 *
576 * On external journals the journal blocks are identity-mapped, so
577 * this is a no-op. If needed, we can use j_blk_offset - everything is
578 * ready.
579 */
580int journal_bmap(journal_t *journal, unsigned long blocknr,
581 unsigned long *retp)
582{
583 int err = 0;
584 unsigned long ret;
585
586 if (journal->j_inode) {
587 ret = bmap(journal->j_inode, blocknr);
588 if (ret)
589 *retp = ret;
590 else {
591 char b[BDEVNAME_SIZE];
592
593 printk(KERN_ALERT "%s: journal block not found "
594 "at offset %lu on %s\n",
595 __FUNCTION__,
596 blocknr,
597 bdevname(journal->j_dev, b));
598 err = -EIO;
599 __journal_abort_soft(journal, err);
600 }
601 } else {
602 *retp = blocknr; /* +journal->j_blk_offset */
603 }
604 return err;
605}
606
607/*
608 * We play buffer_head aliasing tricks to write data/metadata blocks to
609 * the journal without copying their contents, but for journal
610 * descriptor blocks we do need to generate bona fide buffers.
611 *
612 * After the caller of journal_get_descriptor_buffer() has finished modifying
613 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
614 * But we don't bother doing that, so there will be coherency problems with
615 * mmaps of blockdevs which hold live JBD-controlled filesystems.
616 */
617struct journal_head *journal_get_descriptor_buffer(journal_t *journal)
618{
619 struct buffer_head *bh;
620 unsigned long blocknr;
621 int err;
622
623 err = journal_next_log_block(journal, &blocknr);
624
625 if (err)
626 return NULL;
627
628 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
629 lock_buffer(bh);
630 memset(bh->b_data, 0, journal->j_blocksize);
631 set_buffer_uptodate(bh);
632 unlock_buffer(bh);
633 BUFFER_TRACE(bh, "return this buffer");
634 return journal_add_journal_head(bh);
635}
636
637/*
638 * Management for journal control blocks: functions to create and
639 * destroy journal_t structures, and to initialise and read existing
640 * journal blocks from disk. */
641
642/* First: create and setup a journal_t object in memory. We initialise
643 * very few fields yet: that has to wait until we have created the
644 * journal structures from from scratch, or loaded them from disk. */
645
646static journal_t * journal_init_common (void)
647{
648 journal_t *journal;
649 int err;
650
651 journal = jbd_kmalloc(sizeof(*journal), GFP_KERNEL);
652 if (!journal)
653 goto fail;
654 memset(journal, 0, sizeof(*journal));
655
656 init_waitqueue_head(&journal->j_wait_transaction_locked);
657 init_waitqueue_head(&journal->j_wait_logspace);
658 init_waitqueue_head(&journal->j_wait_done_commit);
659 init_waitqueue_head(&journal->j_wait_checkpoint);
660 init_waitqueue_head(&journal->j_wait_commit);
661 init_waitqueue_head(&journal->j_wait_updates);
662 init_MUTEX(&journal->j_barrier);
663 init_MUTEX(&journal->j_checkpoint_sem);
664 spin_lock_init(&journal->j_revoke_lock);
665 spin_lock_init(&journal->j_list_lock);
666 spin_lock_init(&journal->j_state_lock);
667
668 journal->j_commit_interval = (HZ * JBD_DEFAULT_MAX_COMMIT_AGE);
669
670 /* The journal is marked for error until we succeed with recovery! */
671 journal->j_flags = JFS_ABORT;
672
673 /* Set up a default-sized revoke table for the new mount. */
674 err = journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
675 if (err) {
676 kfree(journal);
677 goto fail;
678 }
679 return journal;
680fail:
681 return NULL;
682}
683
684/* journal_init_dev and journal_init_inode:
685 *
686 * Create a journal structure assigned some fixed set of disk blocks to
687 * the journal. We don't actually touch those disk blocks yet, but we
688 * need to set up all of the mapping information to tell the journaling
689 * system where the journal blocks are.
690 *
691 */
692
693/**
694 * journal_t * journal_init_dev() - creates an initialises a journal structure
695 * @bdev: Block device on which to create the journal
696 * @fs_dev: Device which hold journalled filesystem for this journal.
697 * @start: Block nr Start of journal.
698 * @len: Lenght of the journal in blocks.
699 * @blocksize: blocksize of journalling device
700 * @returns: a newly created journal_t *
701 *
702 * journal_init_dev creates a journal which maps a fixed contiguous
703 * range of blocks on an arbitrary block device.
704 *
705 */
706journal_t * journal_init_dev(struct block_device *bdev,
707 struct block_device *fs_dev,
708 int start, int len, int blocksize)
709{
710 journal_t *journal = journal_init_common();
711 struct buffer_head *bh;
712 int n;
713
714 if (!journal)
715 return NULL;
716
717 journal->j_dev = bdev;
718 journal->j_fs_dev = fs_dev;
719 journal->j_blk_offset = start;
720 journal->j_maxlen = len;
721 journal->j_blocksize = blocksize;
722
723 bh = __getblk(journal->j_dev, start, journal->j_blocksize);
724 J_ASSERT(bh != NULL);
725 journal->j_sb_buffer = bh;
726 journal->j_superblock = (journal_superblock_t *)bh->b_data;
727
728 /* journal descriptor can store up to n blocks -bzzz */
729 n = journal->j_blocksize / sizeof(journal_block_tag_t);
730 journal->j_wbufsize = n;
731 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
732 if (!journal->j_wbuf) {
733 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
734 __FUNCTION__);
735 kfree(journal);
736 journal = NULL;
737 }
738
739 return journal;
740}
741
742/**
743 * journal_t * journal_init_inode () - creates a journal which maps to a inode.
744 * @inode: An inode to create the journal in
745 *
746 * journal_init_inode creates a journal which maps an on-disk inode as
747 * the journal. The inode must exist already, must support bmap() and
748 * must have all data blocks preallocated.
749 */
750journal_t * journal_init_inode (struct inode *inode)
751{
752 struct buffer_head *bh;
753 journal_t *journal = journal_init_common();
754 int err;
755 int n;
756 unsigned long blocknr;
757
758 if (!journal)
759 return NULL;
760
761 journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
762 journal->j_inode = inode;
763 jbd_debug(1,
764 "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
765 journal, inode->i_sb->s_id, inode->i_ino,
766 (long long) inode->i_size,
767 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
768
769 journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
770 journal->j_blocksize = inode->i_sb->s_blocksize;
771
772 /* journal descriptor can store up to n blocks -bzzz */
773 n = journal->j_blocksize / sizeof(journal_block_tag_t);
774 journal->j_wbufsize = n;
775 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
776 if (!journal->j_wbuf) {
777 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
778 __FUNCTION__);
779 kfree(journal);
780 return NULL;
781 }
782
783 err = journal_bmap(journal, 0, &blocknr);
784 /* If that failed, give up */
785 if (err) {
786 printk(KERN_ERR "%s: Cannnot locate journal superblock\n",
787 __FUNCTION__);
788 kfree(journal);
789 return NULL;
790 }
791
792 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
793 J_ASSERT(bh != NULL);
794 journal->j_sb_buffer = bh;
795 journal->j_superblock = (journal_superblock_t *)bh->b_data;
796
797 return journal;
798}
799
800/*
801 * If the journal init or create aborts, we need to mark the journal
802 * superblock as being NULL to prevent the journal destroy from writing
803 * back a bogus superblock.
804 */
805static void journal_fail_superblock (journal_t *journal)
806{
807 struct buffer_head *bh = journal->j_sb_buffer;
808 brelse(bh);
809 journal->j_sb_buffer = NULL;
810}
811
812/*
813 * Given a journal_t structure, initialise the various fields for
814 * startup of a new journaling session. We use this both when creating
815 * a journal, and after recovering an old journal to reset it for
816 * subsequent use.
817 */
818
819static int journal_reset(journal_t *journal)
820{
821 journal_superblock_t *sb = journal->j_superblock;
822 unsigned int first, last;
823
824 first = be32_to_cpu(sb->s_first);
825 last = be32_to_cpu(sb->s_maxlen);
826
827 journal->j_first = first;
828 journal->j_last = last;
829
830 journal->j_head = first;
831 journal->j_tail = first;
832 journal->j_free = last - first;
833
834 journal->j_tail_sequence = journal->j_transaction_sequence;
835 journal->j_commit_sequence = journal->j_transaction_sequence - 1;
836 journal->j_commit_request = journal->j_commit_sequence;
837
838 journal->j_max_transaction_buffers = journal->j_maxlen / 4;
839
840 /* Add the dynamic fields and write it to disk. */
841 journal_update_superblock(journal, 1);
842 journal_start_thread(journal);
843 return 0;
844}
845
846/**
847 * int journal_create() - Initialise the new journal file
848 * @journal: Journal to create. This structure must have been initialised
849 *
850 * Given a journal_t structure which tells us which disk blocks we can
851 * use, create a new journal superblock and initialise all of the
852 * journal fields from scratch.
853 **/
854int journal_create(journal_t *journal)
855{
856 unsigned long blocknr;
857 struct buffer_head *bh;
858 journal_superblock_t *sb;
859 int i, err;
860
861 if (journal->j_maxlen < JFS_MIN_JOURNAL_BLOCKS) {
862 printk (KERN_ERR "Journal length (%d blocks) too short.\n",
863 journal->j_maxlen);
864 journal_fail_superblock(journal);
865 return -EINVAL;
866 }
867
868 if (journal->j_inode == NULL) {
869 /*
870 * We don't know what block to start at!
871 */
872 printk(KERN_EMERG
873 "%s: creation of journal on external device!\n",
874 __FUNCTION__);
875 BUG();
876 }
877
878 /* Zero out the entire journal on disk. We cannot afford to
879 have any blocks on disk beginning with JFS_MAGIC_NUMBER. */
880 jbd_debug(1, "JBD: Zeroing out journal blocks...\n");
881 for (i = 0; i < journal->j_maxlen; i++) {
882 err = journal_bmap(journal, i, &blocknr);
883 if (err)
884 return err;
885 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
886 lock_buffer(bh);
887 memset (bh->b_data, 0, journal->j_blocksize);
888 BUFFER_TRACE(bh, "marking dirty");
889 mark_buffer_dirty(bh);
890 BUFFER_TRACE(bh, "marking uptodate");
891 set_buffer_uptodate(bh);
892 unlock_buffer(bh);
893 __brelse(bh);
894 }
895
896 sync_blockdev(journal->j_dev);
897 jbd_debug(1, "JBD: journal cleared.\n");
898
899 /* OK, fill in the initial static fields in the new superblock */
900 sb = journal->j_superblock;
901
902 sb->s_header.h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
903 sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2);
904
905 sb->s_blocksize = cpu_to_be32(journal->j_blocksize);
906 sb->s_maxlen = cpu_to_be32(journal->j_maxlen);
907 sb->s_first = cpu_to_be32(1);
908
909 journal->j_transaction_sequence = 1;
910
911 journal->j_flags &= ~JFS_ABORT;
912 journal->j_format_version = 2;
913
914 return journal_reset(journal);
915}
916
917/**
918 * void journal_update_superblock() - Update journal sb on disk.
919 * @journal: The journal to update.
920 * @wait: Set to '0' if you don't want to wait for IO completion.
921 *
922 * Update a journal's dynamic superblock fields and write it to disk,
923 * optionally waiting for the IO to complete.
924 */
925void journal_update_superblock(journal_t *journal, int wait)
926{
927 journal_superblock_t *sb = journal->j_superblock;
928 struct buffer_head *bh = journal->j_sb_buffer;
929
930 /*
931 * As a special case, if the on-disk copy is already marked as needing
932 * no recovery (s_start == 0) and there are no outstanding transactions
933 * in the filesystem, then we can safely defer the superblock update
934 * until the next commit by setting JFS_FLUSHED. This avoids
935 * attempting a write to a potential-readonly device.
936 */
937 if (sb->s_start == 0 && journal->j_tail_sequence ==
938 journal->j_transaction_sequence) {
939 jbd_debug(1,"JBD: Skipping superblock update on recovered sb "
940 "(start %ld, seq %d, errno %d)\n",
941 journal->j_tail, journal->j_tail_sequence,
942 journal->j_errno);
943 goto out;
944 }
945
946 spin_lock(&journal->j_state_lock);
947 jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n",
948 journal->j_tail, journal->j_tail_sequence, journal->j_errno);
949
950 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
951 sb->s_start = cpu_to_be32(journal->j_tail);
952 sb->s_errno = cpu_to_be32(journal->j_errno);
953 spin_unlock(&journal->j_state_lock);
954
955 BUFFER_TRACE(bh, "marking dirty");
956 mark_buffer_dirty(bh);
957 if (wait)
958 sync_dirty_buffer(bh);
959 else
960 ll_rw_block(WRITE, 1, &bh);
961
962out:
963 /* If we have just flushed the log (by marking s_start==0), then
964 * any future commit will have to be careful to update the
965 * superblock again to re-record the true start of the log. */
966
967 spin_lock(&journal->j_state_lock);
968 if (sb->s_start)
969 journal->j_flags &= ~JFS_FLUSHED;
970 else
971 journal->j_flags |= JFS_FLUSHED;
972 spin_unlock(&journal->j_state_lock);
973}
974
975/*
976 * Read the superblock for a given journal, performing initial
977 * validation of the format.
978 */
979
980static int journal_get_superblock(journal_t *journal)
981{
982 struct buffer_head *bh;
983 journal_superblock_t *sb;
984 int err = -EIO;
985
986 bh = journal->j_sb_buffer;
987
988 J_ASSERT(bh != NULL);
989 if (!buffer_uptodate(bh)) {
990 ll_rw_block(READ, 1, &bh);
991 wait_on_buffer(bh);
992 if (!buffer_uptodate(bh)) {
993 printk (KERN_ERR
994 "JBD: IO error reading journal superblock\n");
995 goto out;
996 }
997 }
998
999 sb = journal->j_superblock;
1000
1001 err = -EINVAL;
1002
1003 if (sb->s_header.h_magic != cpu_to_be32(JFS_MAGIC_NUMBER) ||
1004 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1005 printk(KERN_WARNING "JBD: no valid journal superblock found\n");
1006 goto out;
1007 }
1008
1009 switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1010 case JFS_SUPERBLOCK_V1:
1011 journal->j_format_version = 1;
1012 break;
1013 case JFS_SUPERBLOCK_V2:
1014 journal->j_format_version = 2;
1015 break;
1016 default:
1017 printk(KERN_WARNING "JBD: unrecognised superblock format ID\n");
1018 goto out;
1019 }
1020
1021 if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
1022 journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
1023 else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
1024 printk (KERN_WARNING "JBD: journal file too short\n");
1025 goto out;
1026 }
1027
1028 return 0;
1029
1030out:
1031 journal_fail_superblock(journal);
1032 return err;
1033}
1034
1035/*
1036 * Load the on-disk journal superblock and read the key fields into the
1037 * journal_t.
1038 */
1039
1040static int load_superblock(journal_t *journal)
1041{
1042 int err;
1043 journal_superblock_t *sb;
1044
1045 err = journal_get_superblock(journal);
1046 if (err)
1047 return err;
1048
1049 sb = journal->j_superblock;
1050
1051 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1052 journal->j_tail = be32_to_cpu(sb->s_start);
1053 journal->j_first = be32_to_cpu(sb->s_first);
1054 journal->j_last = be32_to_cpu(sb->s_maxlen);
1055 journal->j_errno = be32_to_cpu(sb->s_errno);
1056
1057 return 0;
1058}
1059
1060
1061/**
1062 * int journal_load() - Read journal from disk.
1063 * @journal: Journal to act on.
1064 *
1065 * Given a journal_t structure which tells us which disk blocks contain
1066 * a journal, read the journal from disk to initialise the in-memory
1067 * structures.
1068 */
1069int journal_load(journal_t *journal)
1070{
1071 int err;
1072
1073 err = load_superblock(journal);
1074 if (err)
1075 return err;
1076
1077 /* If this is a V2 superblock, then we have to check the
1078 * features flags on it. */
1079
1080 if (journal->j_format_version >= 2) {
1081 journal_superblock_t *sb = journal->j_superblock;
1082
1083 if ((sb->s_feature_ro_compat &
1084 ~cpu_to_be32(JFS_KNOWN_ROCOMPAT_FEATURES)) ||
1085 (sb->s_feature_incompat &
1086 ~cpu_to_be32(JFS_KNOWN_INCOMPAT_FEATURES))) {
1087 printk (KERN_WARNING
1088 "JBD: Unrecognised features on journal\n");
1089 return -EINVAL;
1090 }
1091 }
1092
1093 /* Let the recovery code check whether it needs to recover any
1094 * data from the journal. */
1095 if (journal_recover(journal))
1096 goto recovery_error;
1097
1098 /* OK, we've finished with the dynamic journal bits:
1099 * reinitialise the dynamic contents of the superblock in memory
1100 * and reset them on disk. */
1101 if (journal_reset(journal))
1102 goto recovery_error;
1103
1104 journal->j_flags &= ~JFS_ABORT;
1105 journal->j_flags |= JFS_LOADED;
1106 return 0;
1107
1108recovery_error:
1109 printk (KERN_WARNING "JBD: recovery failed\n");
1110 return -EIO;
1111}
1112
1113/**
1114 * void journal_destroy() - Release a journal_t structure.
1115 * @journal: Journal to act on.
1116 *
1117 * Release a journal_t structure once it is no longer in use by the
1118 * journaled object.
1119 */
1120void journal_destroy(journal_t *journal)
1121{
1122 /* Wait for the commit thread to wake up and die. */
1123 journal_kill_thread(journal);
1124
1125 /* Force a final log commit */
1126 if (journal->j_running_transaction)
1127 journal_commit_transaction(journal);
1128
1129 /* Force any old transactions to disk */
1130
1131 /* Totally anal locking here... */
1132 spin_lock(&journal->j_list_lock);
1133 while (journal->j_checkpoint_transactions != NULL) {
1134 spin_unlock(&journal->j_list_lock);
1135 log_do_checkpoint(journal);
1136 spin_lock(&journal->j_list_lock);
1137 }
1138
1139 J_ASSERT(journal->j_running_transaction == NULL);
1140 J_ASSERT(journal->j_committing_transaction == NULL);
1141 J_ASSERT(journal->j_checkpoint_transactions == NULL);
1142 spin_unlock(&journal->j_list_lock);
1143
1144 /* We can now mark the journal as empty. */
1145 journal->j_tail = 0;
1146 journal->j_tail_sequence = ++journal->j_transaction_sequence;
1147 if (journal->j_sb_buffer) {
1148 journal_update_superblock(journal, 1);
1149 brelse(journal->j_sb_buffer);
1150 }
1151
1152 if (journal->j_inode)
1153 iput(journal->j_inode);
1154 if (journal->j_revoke)
1155 journal_destroy_revoke(journal);
1156 kfree(journal->j_wbuf);
1157 kfree(journal);
1158}
1159
1160
1161/**
1162 *int journal_check_used_features () - Check if features specified are used.
1163 * @journal: Journal to check.
1164 * @compat: bitmask of compatible features
1165 * @ro: bitmask of features that force read-only mount
1166 * @incompat: bitmask of incompatible features
1167 *
1168 * Check whether the journal uses all of a given set of
1169 * features. Return true (non-zero) if it does.
1170 **/
1171
1172int journal_check_used_features (journal_t *journal, unsigned long compat,
1173 unsigned long ro, unsigned long incompat)
1174{
1175 journal_superblock_t *sb;
1176
1177 if (!compat && !ro && !incompat)
1178 return 1;
1179 if (journal->j_format_version == 1)
1180 return 0;
1181
1182 sb = journal->j_superblock;
1183
1184 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
1185 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
1186 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
1187 return 1;
1188
1189 return 0;
1190}
1191
1192/**
1193 * int journal_check_available_features() - Check feature set in journalling layer
1194 * @journal: Journal to check.
1195 * @compat: bitmask of compatible features
1196 * @ro: bitmask of features that force read-only mount
1197 * @incompat: bitmask of incompatible features
1198 *
1199 * Check whether the journaling code supports the use of
1200 * all of a given set of features on this journal. Return true
1201 * (non-zero) if it can. */
1202
1203int journal_check_available_features (journal_t *journal, unsigned long compat,
1204 unsigned long ro, unsigned long incompat)
1205{
1206 journal_superblock_t *sb;
1207
1208 if (!compat && !ro && !incompat)
1209 return 1;
1210
1211 sb = journal->j_superblock;
1212
1213 /* We can support any known requested features iff the
1214 * superblock is in version 2. Otherwise we fail to support any
1215 * extended sb features. */
1216
1217 if (journal->j_format_version != 2)
1218 return 0;
1219
1220 if ((compat & JFS_KNOWN_COMPAT_FEATURES) == compat &&
1221 (ro & JFS_KNOWN_ROCOMPAT_FEATURES) == ro &&
1222 (incompat & JFS_KNOWN_INCOMPAT_FEATURES) == incompat)
1223 return 1;
1224
1225 return 0;
1226}
1227
1228/**
1229 * int journal_set_features () - Mark a given journal feature in the superblock
1230 * @journal: Journal to act on.
1231 * @compat: bitmask of compatible features
1232 * @ro: bitmask of features that force read-only mount
1233 * @incompat: bitmask of incompatible features
1234 *
1235 * Mark a given journal feature as present on the
1236 * superblock. Returns true if the requested features could be set.
1237 *
1238 */
1239
1240int journal_set_features (journal_t *journal, unsigned long compat,
1241 unsigned long ro, unsigned long incompat)
1242{
1243 journal_superblock_t *sb;
1244
1245 if (journal_check_used_features(journal, compat, ro, incompat))
1246 return 1;
1247
1248 if (!journal_check_available_features(journal, compat, ro, incompat))
1249 return 0;
1250
1251 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1252 compat, ro, incompat);
1253
1254 sb = journal->j_superblock;
1255
1256 sb->s_feature_compat |= cpu_to_be32(compat);
1257 sb->s_feature_ro_compat |= cpu_to_be32(ro);
1258 sb->s_feature_incompat |= cpu_to_be32(incompat);
1259
1260 return 1;
1261}
1262
1263
1264/**
1265 * int journal_update_format () - Update on-disk journal structure.
1266 * @journal: Journal to act on.
1267 *
1268 * Given an initialised but unloaded journal struct, poke about in the
1269 * on-disk structure to update it to the most recent supported version.
1270 */
1271int journal_update_format (journal_t *journal)
1272{
1273 journal_superblock_t *sb;
1274 int err;
1275
1276 err = journal_get_superblock(journal);
1277 if (err)
1278 return err;
1279
1280 sb = journal->j_superblock;
1281
1282 switch (be32_to_cpu(sb->s_header.h_blocktype)) {
1283 case JFS_SUPERBLOCK_V2:
1284 return 0;
1285 case JFS_SUPERBLOCK_V1:
1286 return journal_convert_superblock_v1(journal, sb);
1287 default:
1288 break;
1289 }
1290 return -EINVAL;
1291}
1292
1293static int journal_convert_superblock_v1(journal_t *journal,
1294 journal_superblock_t *sb)
1295{
1296 int offset, blocksize;
1297 struct buffer_head *bh;
1298
1299 printk(KERN_WARNING
1300 "JBD: Converting superblock from version 1 to 2.\n");
1301
1302 /* Pre-initialise new fields to zero */
1303 offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
1304 blocksize = be32_to_cpu(sb->s_blocksize);
1305 memset(&sb->s_feature_compat, 0, blocksize-offset);
1306
1307 sb->s_nr_users = cpu_to_be32(1);
1308 sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2);
1309 journal->j_format_version = 2;
1310
1311 bh = journal->j_sb_buffer;
1312 BUFFER_TRACE(bh, "marking dirty");
1313 mark_buffer_dirty(bh);
1314 sync_dirty_buffer(bh);
1315 return 0;
1316}
1317
1318
1319/**
1320 * int journal_flush () - Flush journal
1321 * @journal: Journal to act on.
1322 *
1323 * Flush all data for a given journal to disk and empty the journal.
1324 * Filesystems can use this when remounting readonly to ensure that
1325 * recovery does not need to happen on remount.
1326 */
1327
1328int journal_flush(journal_t *journal)
1329{
1330 int err = 0;
1331 transaction_t *transaction = NULL;
1332 unsigned long old_tail;
1333
1334 spin_lock(&journal->j_state_lock);
1335
1336 /* Force everything buffered to the log... */
1337 if (journal->j_running_transaction) {
1338 transaction = journal->j_running_transaction;
1339 __log_start_commit(journal, transaction->t_tid);
1340 } else if (journal->j_committing_transaction)
1341 transaction = journal->j_committing_transaction;
1342
1343 /* Wait for the log commit to complete... */
1344 if (transaction) {
1345 tid_t tid = transaction->t_tid;
1346
1347 spin_unlock(&journal->j_state_lock);
1348 log_wait_commit(journal, tid);
1349 } else {
1350 spin_unlock(&journal->j_state_lock);
1351 }
1352
1353 /* ...and flush everything in the log out to disk. */
1354 spin_lock(&journal->j_list_lock);
1355 while (!err && journal->j_checkpoint_transactions != NULL) {
1356 spin_unlock(&journal->j_list_lock);
1357 err = log_do_checkpoint(journal);
1358 spin_lock(&journal->j_list_lock);
1359 }
1360 spin_unlock(&journal->j_list_lock);
1361 cleanup_journal_tail(journal);
1362
1363 /* Finally, mark the journal as really needing no recovery.
1364 * This sets s_start==0 in the underlying superblock, which is
1365 * the magic code for a fully-recovered superblock. Any future
1366 * commits of data to the journal will restore the current
1367 * s_start value. */
1368 spin_lock(&journal->j_state_lock);
1369 old_tail = journal->j_tail;
1370 journal->j_tail = 0;
1371 spin_unlock(&journal->j_state_lock);
1372 journal_update_superblock(journal, 1);
1373 spin_lock(&journal->j_state_lock);
1374 journal->j_tail = old_tail;
1375
1376 J_ASSERT(!journal->j_running_transaction);
1377 J_ASSERT(!journal->j_committing_transaction);
1378 J_ASSERT(!journal->j_checkpoint_transactions);
1379 J_ASSERT(journal->j_head == journal->j_tail);
1380 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
1381 spin_unlock(&journal->j_state_lock);
1382 return err;
1383}
1384
1385/**
1386 * int journal_wipe() - Wipe journal contents
1387 * @journal: Journal to act on.
1388 * @write: flag (see below)
1389 *
1390 * Wipe out all of the contents of a journal, safely. This will produce
1391 * a warning if the journal contains any valid recovery information.
1392 * Must be called between journal_init_*() and journal_load().
1393 *
1394 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
1395 * we merely suppress recovery.
1396 */
1397
1398int journal_wipe(journal_t *journal, int write)
1399{
1400 journal_superblock_t *sb;
1401 int err = 0;
1402
1403 J_ASSERT (!(journal->j_flags & JFS_LOADED));
1404
1405 err = load_superblock(journal);
1406 if (err)
1407 return err;
1408
1409 sb = journal->j_superblock;
1410
1411 if (!journal->j_tail)
1412 goto no_recovery;
1413
1414 printk (KERN_WARNING "JBD: %s recovery information on journal\n",
1415 write ? "Clearing" : "Ignoring");
1416
1417 err = journal_skip_recovery(journal);
1418 if (write)
1419 journal_update_superblock(journal, 1);
1420
1421 no_recovery:
1422 return err;
1423}
1424
1425/*
1426 * journal_dev_name: format a character string to describe on what
1427 * device this journal is present.
1428 */
1429
Adrian Bunk022a4a72005-09-06 15:16:41 -07001430static const char *journal_dev_name(journal_t *journal, char *buffer)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431{
1432 struct block_device *bdev;
1433
1434 if (journal->j_inode)
1435 bdev = journal->j_inode->i_sb->s_bdev;
1436 else
1437 bdev = journal->j_dev;
1438
1439 return bdevname(bdev, buffer);
1440}
1441
1442/*
1443 * Journal abort has very specific semantics, which we describe
1444 * for journal abort.
1445 *
1446 * Two internal function, which provide abort to te jbd layer
1447 * itself are here.
1448 */
1449
1450/*
1451 * Quick version for internal journal use (doesn't lock the journal).
1452 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
1453 * and don't attempt to make any other journal updates.
1454 */
1455void __journal_abort_hard(journal_t *journal)
1456{
1457 transaction_t *transaction;
1458 char b[BDEVNAME_SIZE];
1459
1460 if (journal->j_flags & JFS_ABORT)
1461 return;
1462
1463 printk(KERN_ERR "Aborting journal on device %s.\n",
1464 journal_dev_name(journal, b));
1465
1466 spin_lock(&journal->j_state_lock);
1467 journal->j_flags |= JFS_ABORT;
1468 transaction = journal->j_running_transaction;
1469 if (transaction)
1470 __log_start_commit(journal, transaction->t_tid);
1471 spin_unlock(&journal->j_state_lock);
1472}
1473
1474/* Soft abort: record the abort error status in the journal superblock,
1475 * but don't do any other IO. */
Adrian Bunk022a4a72005-09-06 15:16:41 -07001476static void __journal_abort_soft (journal_t *journal, int errno)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477{
1478 if (journal->j_flags & JFS_ABORT)
1479 return;
1480
1481 if (!journal->j_errno)
1482 journal->j_errno = errno;
1483
1484 __journal_abort_hard(journal);
1485
1486 if (errno)
1487 journal_update_superblock(journal, 1);
1488}
1489
1490/**
1491 * void journal_abort () - Shutdown the journal immediately.
1492 * @journal: the journal to shutdown.
1493 * @errno: an error number to record in the journal indicating
1494 * the reason for the shutdown.
1495 *
1496 * Perform a complete, immediate shutdown of the ENTIRE
1497 * journal (not of a single transaction). This operation cannot be
1498 * undone without closing and reopening the journal.
1499 *
1500 * The journal_abort function is intended to support higher level error
1501 * recovery mechanisms such as the ext2/ext3 remount-readonly error
1502 * mode.
1503 *
1504 * Journal abort has very specific semantics. Any existing dirty,
1505 * unjournaled buffers in the main filesystem will still be written to
1506 * disk by bdflush, but the journaling mechanism will be suspended
1507 * immediately and no further transaction commits will be honoured.
1508 *
1509 * Any dirty, journaled buffers will be written back to disk without
1510 * hitting the journal. Atomicity cannot be guaranteed on an aborted
1511 * filesystem, but we _do_ attempt to leave as much data as possible
1512 * behind for fsck to use for cleanup.
1513 *
1514 * Any attempt to get a new transaction handle on a journal which is in
1515 * ABORT state will just result in an -EROFS error return. A
1516 * journal_stop on an existing handle will return -EIO if we have
1517 * entered abort state during the update.
1518 *
1519 * Recursive transactions are not disturbed by journal abort until the
1520 * final journal_stop, which will receive the -EIO error.
1521 *
1522 * Finally, the journal_abort call allows the caller to supply an errno
1523 * which will be recorded (if possible) in the journal superblock. This
1524 * allows a client to record failure conditions in the middle of a
1525 * transaction without having to complete the transaction to record the
1526 * failure to disk. ext3_error, for example, now uses this
1527 * functionality.
1528 *
1529 * Errors which originate from within the journaling layer will NOT
1530 * supply an errno; a null errno implies that absolutely no further
1531 * writes are done to the journal (unless there are any already in
1532 * progress).
1533 *
1534 */
1535
1536void journal_abort(journal_t *journal, int errno)
1537{
1538 __journal_abort_soft(journal, errno);
1539}
1540
1541/**
1542 * int journal_errno () - returns the journal's error state.
1543 * @journal: journal to examine.
1544 *
1545 * This is the errno numbet set with journal_abort(), the last
1546 * time the journal was mounted - if the journal was stopped
1547 * without calling abort this will be 0.
1548 *
1549 * If the journal has been aborted on this mount time -EROFS will
1550 * be returned.
1551 */
1552int journal_errno(journal_t *journal)
1553{
1554 int err;
1555
1556 spin_lock(&journal->j_state_lock);
1557 if (journal->j_flags & JFS_ABORT)
1558 err = -EROFS;
1559 else
1560 err = journal->j_errno;
1561 spin_unlock(&journal->j_state_lock);
1562 return err;
1563}
1564
1565/**
1566 * int journal_clear_err () - clears the journal's error state
1567 * @journal: journal to act on.
1568 *
1569 * An error must be cleared or Acked to take a FS out of readonly
1570 * mode.
1571 */
1572int journal_clear_err(journal_t *journal)
1573{
1574 int err = 0;
1575
1576 spin_lock(&journal->j_state_lock);
1577 if (journal->j_flags & JFS_ABORT)
1578 err = -EROFS;
1579 else
1580 journal->j_errno = 0;
1581 spin_unlock(&journal->j_state_lock);
1582 return err;
1583}
1584
1585/**
1586 * void journal_ack_err() - Ack journal err.
1587 * @journal: journal to act on.
1588 *
1589 * An error must be cleared or Acked to take a FS out of readonly
1590 * mode.
1591 */
1592void journal_ack_err(journal_t *journal)
1593{
1594 spin_lock(&journal->j_state_lock);
1595 if (journal->j_errno)
1596 journal->j_flags |= JFS_ACK_ERR;
1597 spin_unlock(&journal->j_state_lock);
1598}
1599
1600int journal_blocks_per_page(struct inode *inode)
1601{
1602 return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
1603}
1604
1605/*
1606 * Simple support for retrying memory allocations. Introduced to help to
1607 * debug different VM deadlock avoidance strategies.
1608 */
1609void * __jbd_kmalloc (const char *where, size_t size, int flags, int retry)
1610{
1611 return kmalloc(size, flags | (retry ? __GFP_NOFAIL : 0));
1612}
1613
1614/*
1615 * Journal_head storage management
1616 */
1617static kmem_cache_t *journal_head_cache;
1618#ifdef CONFIG_JBD_DEBUG
1619static atomic_t nr_journal_heads = ATOMIC_INIT(0);
1620#endif
1621
1622static int journal_init_journal_head_cache(void)
1623{
1624 int retval;
1625
1626 J_ASSERT(journal_head_cache == 0);
1627 journal_head_cache = kmem_cache_create("journal_head",
1628 sizeof(struct journal_head),
1629 0, /* offset */
1630 0, /* flags */
1631 NULL, /* ctor */
1632 NULL); /* dtor */
1633 retval = 0;
1634 if (journal_head_cache == 0) {
1635 retval = -ENOMEM;
1636 printk(KERN_EMERG "JBD: no memory for journal_head cache\n");
1637 }
1638 return retval;
1639}
1640
1641static void journal_destroy_journal_head_cache(void)
1642{
1643 J_ASSERT(journal_head_cache != NULL);
1644 kmem_cache_destroy(journal_head_cache);
1645 journal_head_cache = NULL;
1646}
1647
1648/*
1649 * journal_head splicing and dicing
1650 */
1651static struct journal_head *journal_alloc_journal_head(void)
1652{
1653 struct journal_head *ret;
1654 static unsigned long last_warning;
1655
1656#ifdef CONFIG_JBD_DEBUG
1657 atomic_inc(&nr_journal_heads);
1658#endif
1659 ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS);
1660 if (ret == 0) {
1661 jbd_debug(1, "out of memory for journal_head\n");
1662 if (time_after(jiffies, last_warning + 5*HZ)) {
1663 printk(KERN_NOTICE "ENOMEM in %s, retrying.\n",
1664 __FUNCTION__);
1665 last_warning = jiffies;
1666 }
1667 while (ret == 0) {
1668 yield();
1669 ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS);
1670 }
1671 }
1672 return ret;
1673}
1674
1675static void journal_free_journal_head(struct journal_head *jh)
1676{
1677#ifdef CONFIG_JBD_DEBUG
1678 atomic_dec(&nr_journal_heads);
1679 memset(jh, 0x5b, sizeof(*jh));
1680#endif
1681 kmem_cache_free(journal_head_cache, jh);
1682}
1683
1684/*
1685 * A journal_head is attached to a buffer_head whenever JBD has an
1686 * interest in the buffer.
1687 *
1688 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
1689 * is set. This bit is tested in core kernel code where we need to take
1690 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
1691 * there.
1692 *
1693 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
1694 *
1695 * When a buffer has its BH_JBD bit set it is immune from being released by
1696 * core kernel code, mainly via ->b_count.
1697 *
1698 * A journal_head may be detached from its buffer_head when the journal_head's
1699 * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL.
1700 * Various places in JBD call journal_remove_journal_head() to indicate that the
1701 * journal_head can be dropped if needed.
1702 *
1703 * Various places in the kernel want to attach a journal_head to a buffer_head
1704 * _before_ attaching the journal_head to a transaction. To protect the
1705 * journal_head in this situation, journal_add_journal_head elevates the
1706 * journal_head's b_jcount refcount by one. The caller must call
1707 * journal_put_journal_head() to undo this.
1708 *
1709 * So the typical usage would be:
1710 *
1711 * (Attach a journal_head if needed. Increments b_jcount)
1712 * struct journal_head *jh = journal_add_journal_head(bh);
1713 * ...
1714 * jh->b_transaction = xxx;
1715 * journal_put_journal_head(jh);
1716 *
1717 * Now, the journal_head's b_jcount is zero, but it is safe from being released
1718 * because it has a non-zero b_transaction.
1719 */
1720
1721/*
1722 * Give a buffer_head a journal_head.
1723 *
1724 * Doesn't need the journal lock.
1725 * May sleep.
1726 */
1727struct journal_head *journal_add_journal_head(struct buffer_head *bh)
1728{
1729 struct journal_head *jh;
1730 struct journal_head *new_jh = NULL;
1731
1732repeat:
1733 if (!buffer_jbd(bh)) {
1734 new_jh = journal_alloc_journal_head();
1735 memset(new_jh, 0, sizeof(*new_jh));
1736 }
1737
1738 jbd_lock_bh_journal_head(bh);
1739 if (buffer_jbd(bh)) {
1740 jh = bh2jh(bh);
1741 } else {
1742 J_ASSERT_BH(bh,
1743 (atomic_read(&bh->b_count) > 0) ||
1744 (bh->b_page && bh->b_page->mapping));
1745
1746 if (!new_jh) {
1747 jbd_unlock_bh_journal_head(bh);
1748 goto repeat;
1749 }
1750
1751 jh = new_jh;
1752 new_jh = NULL; /* We consumed it */
1753 set_buffer_jbd(bh);
1754 bh->b_private = jh;
1755 jh->b_bh = bh;
1756 get_bh(bh);
1757 BUFFER_TRACE(bh, "added journal_head");
1758 }
1759 jh->b_jcount++;
1760 jbd_unlock_bh_journal_head(bh);
1761 if (new_jh)
1762 journal_free_journal_head(new_jh);
1763 return bh->b_private;
1764}
1765
1766/*
1767 * Grab a ref against this buffer_head's journal_head. If it ended up not
1768 * having a journal_head, return NULL
1769 */
1770struct journal_head *journal_grab_journal_head(struct buffer_head *bh)
1771{
1772 struct journal_head *jh = NULL;
1773
1774 jbd_lock_bh_journal_head(bh);
1775 if (buffer_jbd(bh)) {
1776 jh = bh2jh(bh);
1777 jh->b_jcount++;
1778 }
1779 jbd_unlock_bh_journal_head(bh);
1780 return jh;
1781}
1782
1783static void __journal_remove_journal_head(struct buffer_head *bh)
1784{
1785 struct journal_head *jh = bh2jh(bh);
1786
1787 J_ASSERT_JH(jh, jh->b_jcount >= 0);
1788
1789 get_bh(bh);
1790 if (jh->b_jcount == 0) {
1791 if (jh->b_transaction == NULL &&
1792 jh->b_next_transaction == NULL &&
1793 jh->b_cp_transaction == NULL) {
1794 J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
1795 J_ASSERT_BH(bh, buffer_jbd(bh));
1796 J_ASSERT_BH(bh, jh2bh(jh) == bh);
1797 BUFFER_TRACE(bh, "remove journal_head");
1798 if (jh->b_frozen_data) {
1799 printk(KERN_WARNING "%s: freeing "
1800 "b_frozen_data\n",
1801 __FUNCTION__);
1802 kfree(jh->b_frozen_data);
1803 }
1804 if (jh->b_committed_data) {
1805 printk(KERN_WARNING "%s: freeing "
1806 "b_committed_data\n",
1807 __FUNCTION__);
1808 kfree(jh->b_committed_data);
1809 }
1810 bh->b_private = NULL;
1811 jh->b_bh = NULL; /* debug, really */
1812 clear_buffer_jbd(bh);
1813 __brelse(bh);
1814 journal_free_journal_head(jh);
1815 } else {
1816 BUFFER_TRACE(bh, "journal_head was locked");
1817 }
1818 }
1819}
1820
1821/*
1822 * journal_remove_journal_head(): if the buffer isn't attached to a transaction
1823 * and has a zero b_jcount then remove and release its journal_head. If we did
1824 * see that the buffer is not used by any transaction we also "logically"
1825 * decrement ->b_count.
1826 *
1827 * We in fact take an additional increment on ->b_count as a convenience,
1828 * because the caller usually wants to do additional things with the bh
1829 * after calling here.
1830 * The caller of journal_remove_journal_head() *must* run __brelse(bh) at some
1831 * time. Once the caller has run __brelse(), the buffer is eligible for
1832 * reaping by try_to_free_buffers().
1833 */
1834void journal_remove_journal_head(struct buffer_head *bh)
1835{
1836 jbd_lock_bh_journal_head(bh);
1837 __journal_remove_journal_head(bh);
1838 jbd_unlock_bh_journal_head(bh);
1839}
1840
1841/*
1842 * Drop a reference on the passed journal_head. If it fell to zero then try to
1843 * release the journal_head from the buffer_head.
1844 */
1845void journal_put_journal_head(struct journal_head *jh)
1846{
1847 struct buffer_head *bh = jh2bh(jh);
1848
1849 jbd_lock_bh_journal_head(bh);
1850 J_ASSERT_JH(jh, jh->b_jcount > 0);
1851 --jh->b_jcount;
1852 if (!jh->b_jcount && !jh->b_transaction) {
1853 __journal_remove_journal_head(bh);
1854 __brelse(bh);
1855 }
1856 jbd_unlock_bh_journal_head(bh);
1857}
1858
1859/*
1860 * /proc tunables
1861 */
1862#if defined(CONFIG_JBD_DEBUG)
1863int journal_enable_debug;
1864EXPORT_SYMBOL(journal_enable_debug);
1865#endif
1866
1867#if defined(CONFIG_JBD_DEBUG) && defined(CONFIG_PROC_FS)
1868
1869static struct proc_dir_entry *proc_jbd_debug;
1870
Adrian Bunk022a4a72005-09-06 15:16:41 -07001871static int read_jbd_debug(char *page, char **start, off_t off,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001872 int count, int *eof, void *data)
1873{
1874 int ret;
1875
1876 ret = sprintf(page + off, "%d\n", journal_enable_debug);
1877 *eof = 1;
1878 return ret;
1879}
1880
Adrian Bunk022a4a72005-09-06 15:16:41 -07001881static int write_jbd_debug(struct file *file, const char __user *buffer,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882 unsigned long count, void *data)
1883{
1884 char buf[32];
1885
1886 if (count > ARRAY_SIZE(buf) - 1)
1887 count = ARRAY_SIZE(buf) - 1;
1888 if (copy_from_user(buf, buffer, count))
1889 return -EFAULT;
1890 buf[ARRAY_SIZE(buf) - 1] = '\0';
1891 journal_enable_debug = simple_strtoul(buf, NULL, 10);
1892 return count;
1893}
1894
1895#define JBD_PROC_NAME "sys/fs/jbd-debug"
1896
1897static void __init create_jbd_proc_entry(void)
1898{
1899 proc_jbd_debug = create_proc_entry(JBD_PROC_NAME, 0644, NULL);
1900 if (proc_jbd_debug) {
1901 /* Why is this so hard? */
1902 proc_jbd_debug->read_proc = read_jbd_debug;
1903 proc_jbd_debug->write_proc = write_jbd_debug;
1904 }
1905}
1906
1907static void __exit remove_jbd_proc_entry(void)
1908{
1909 if (proc_jbd_debug)
1910 remove_proc_entry(JBD_PROC_NAME, NULL);
1911}
1912
1913#else
1914
1915#define create_jbd_proc_entry() do {} while (0)
1916#define remove_jbd_proc_entry() do {} while (0)
1917
1918#endif
1919
1920kmem_cache_t *jbd_handle_cache;
1921
1922static int __init journal_init_handle_cache(void)
1923{
1924 jbd_handle_cache = kmem_cache_create("journal_handle",
1925 sizeof(handle_t),
1926 0, /* offset */
1927 0, /* flags */
1928 NULL, /* ctor */
1929 NULL); /* dtor */
1930 if (jbd_handle_cache == NULL) {
1931 printk(KERN_EMERG "JBD: failed to create handle cache\n");
1932 return -ENOMEM;
1933 }
1934 return 0;
1935}
1936
1937static void journal_destroy_handle_cache(void)
1938{
1939 if (jbd_handle_cache)
1940 kmem_cache_destroy(jbd_handle_cache);
1941}
1942
1943/*
1944 * Module startup and shutdown
1945 */
1946
1947static int __init journal_init_caches(void)
1948{
1949 int ret;
1950
1951 ret = journal_init_revoke_caches();
1952 if (ret == 0)
1953 ret = journal_init_journal_head_cache();
1954 if (ret == 0)
1955 ret = journal_init_handle_cache();
1956 return ret;
1957}
1958
1959static void journal_destroy_caches(void)
1960{
1961 journal_destroy_revoke_caches();
1962 journal_destroy_journal_head_cache();
1963 journal_destroy_handle_cache();
1964}
1965
1966static int __init journal_init(void)
1967{
1968 int ret;
1969
Adrian Bunk022a4a72005-09-06 15:16:41 -07001970/* Static check for data structure consistency. There's no code
1971 * invoked --- we'll just get a linker failure if things aren't right.
1972 */
1973 extern void journal_bad_superblock_size(void);
1974 if (sizeof(struct journal_superblock_s) != 1024)
1975 journal_bad_superblock_size();
1976
1977
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978 ret = journal_init_caches();
1979 if (ret != 0)
1980 journal_destroy_caches();
1981 create_jbd_proc_entry();
1982 return ret;
1983}
1984
1985static void __exit journal_exit(void)
1986{
1987#ifdef CONFIG_JBD_DEBUG
1988 int n = atomic_read(&nr_journal_heads);
1989 if (n)
1990 printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n);
1991#endif
1992 remove_jbd_proc_entry();
1993 journal_destroy_caches();
1994}
1995
1996MODULE_LICENSE("GPL");
1997module_init(journal_init);
1998module_exit(journal_exit);
1999