2 * linux/fs/jbd2/journal.c
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
6 * Copyright 1998 Red Hat corp --- All Rights Reserved
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.
12 * Generic filesystem journal-writing code; part of the ext2fs
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.
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).
25 #include <linux/module.h>
26 #include <linux/time.h>
28 #include <linux/jbd2.h>
29 #include <linux/errno.h>
30 #include <linux/slab.h>
31 #include <linux/init.h>
33 #include <linux/freezer.h>
34 #include <linux/pagemap.h>
35 #include <linux/kthread.h>
36 #include <linux/poison.h>
37 #include <linux/proc_fs.h>
38 #include <linux/debugfs.h>
39 #include <linux/seq_file.h>
40 #include <linux/math64.h>
41 #include <linux/hash.h>
43 #define CREATE_TRACE_POINTS
44 #include <trace/events/jbd2.h>
46 #include <asm/uaccess.h>
49 EXPORT_SYMBOL(jbd2_journal_start);
50 EXPORT_SYMBOL(jbd2_journal_restart);
51 EXPORT_SYMBOL(jbd2_journal_extend);
52 EXPORT_SYMBOL(jbd2_journal_stop);
53 EXPORT_SYMBOL(jbd2_journal_lock_updates);
54 EXPORT_SYMBOL(jbd2_journal_unlock_updates);
55 EXPORT_SYMBOL(jbd2_journal_get_write_access);
56 EXPORT_SYMBOL(jbd2_journal_get_create_access);
57 EXPORT_SYMBOL(jbd2_journal_get_undo_access);
58 EXPORT_SYMBOL(jbd2_journal_set_triggers);
59 EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
60 EXPORT_SYMBOL(jbd2_journal_release_buffer);
61 EXPORT_SYMBOL(jbd2_journal_forget);
63 EXPORT_SYMBOL(journal_sync_buffer);
65 EXPORT_SYMBOL(jbd2_journal_flush);
66 EXPORT_SYMBOL(jbd2_journal_revoke);
68 EXPORT_SYMBOL(jbd2_journal_init_dev);
69 EXPORT_SYMBOL(jbd2_journal_init_inode);
70 EXPORT_SYMBOL(jbd2_journal_update_format);
71 EXPORT_SYMBOL(jbd2_journal_check_used_features);
72 EXPORT_SYMBOL(jbd2_journal_check_available_features);
73 EXPORT_SYMBOL(jbd2_journal_set_features);
74 EXPORT_SYMBOL(jbd2_journal_load);
75 EXPORT_SYMBOL(jbd2_journal_destroy);
76 EXPORT_SYMBOL(jbd2_journal_abort);
77 EXPORT_SYMBOL(jbd2_journal_errno);
78 EXPORT_SYMBOL(jbd2_journal_ack_err);
79 EXPORT_SYMBOL(jbd2_journal_clear_err);
80 EXPORT_SYMBOL(jbd2_log_wait_commit);
81 EXPORT_SYMBOL(jbd2_journal_start_commit);
82 EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
83 EXPORT_SYMBOL(jbd2_journal_wipe);
84 EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
85 EXPORT_SYMBOL(jbd2_journal_invalidatepage);
86 EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
87 EXPORT_SYMBOL(jbd2_journal_force_commit);
88 EXPORT_SYMBOL(jbd2_journal_file_inode);
89 EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
90 EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
91 EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
93 static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
94 static void __journal_abort_soft (journal_t *journal, int errno);
97 * Helper function used to manage commit timeouts
100 static void commit_timeout(unsigned long __data)
102 struct task_struct * p = (struct task_struct *) __data;
108 * kjournald2: The main thread function used to manage a logging device
111 * This kernel thread is responsible for two things:
113 * 1) COMMIT: Every so often we need to commit the current state of the
114 * filesystem to disk. The journal thread is responsible for writing
115 * all of the metadata buffers to disk.
117 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
118 * of the data in that part of the log has been rewritten elsewhere on
119 * the disk. Flushing these old buffers to reclaim space in the log is
120 * known as checkpointing, and this thread is responsible for that job.
123 static int kjournald2(void *arg)
125 journal_t *journal = arg;
126 transaction_t *transaction;
129 * Set up an interval timer which can be used to trigger a commit wakeup
130 * after the commit interval expires
132 setup_timer(&journal->j_commit_timer, commit_timeout,
133 (unsigned long)current);
135 /* Record that the journal thread is running */
136 journal->j_task = current;
137 wake_up(&journal->j_wait_done_commit);
140 * And now, wait forever for commit wakeup events.
142 spin_lock(&journal->j_state_lock);
145 if (journal->j_flags & JBD2_UNMOUNT)
148 jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
149 journal->j_commit_sequence, journal->j_commit_request);
151 if (journal->j_commit_sequence != journal->j_commit_request) {
152 jbd_debug(1, "OK, requests differ\n");
153 spin_unlock(&journal->j_state_lock);
154 del_timer_sync(&journal->j_commit_timer);
155 jbd2_journal_commit_transaction(journal);
156 spin_lock(&journal->j_state_lock);
160 wake_up(&journal->j_wait_done_commit);
161 if (freezing(current)) {
163 * The simpler the better. Flushing journal isn't a
164 * good idea, because that depends on threads that may
165 * be already stopped.
167 jbd_debug(1, "Now suspending kjournald2\n");
168 spin_unlock(&journal->j_state_lock);
170 spin_lock(&journal->j_state_lock);
173 * We assume on resume that commits are already there,
177 int should_sleep = 1;
179 prepare_to_wait(&journal->j_wait_commit, &wait,
181 if (journal->j_commit_sequence != journal->j_commit_request)
183 transaction = journal->j_running_transaction;
184 if (transaction && time_after_eq(jiffies,
185 transaction->t_expires))
187 if (journal->j_flags & JBD2_UNMOUNT)
190 spin_unlock(&journal->j_state_lock);
192 spin_lock(&journal->j_state_lock);
194 finish_wait(&journal->j_wait_commit, &wait);
197 jbd_debug(1, "kjournald2 wakes\n");
200 * Were we woken up by a commit wakeup event?
202 transaction = journal->j_running_transaction;
203 if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
204 journal->j_commit_request = transaction->t_tid;
205 jbd_debug(1, "woke because of timeout\n");
210 spin_unlock(&journal->j_state_lock);
211 del_timer_sync(&journal->j_commit_timer);
212 journal->j_task = NULL;
213 wake_up(&journal->j_wait_done_commit);
214 jbd_debug(1, "Journal thread exiting.\n");
218 static int jbd2_journal_start_thread(journal_t *journal)
220 struct task_struct *t;
222 t = kthread_run(kjournald2, journal, "jbd2/%s",
227 wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
231 static void journal_kill_thread(journal_t *journal)
233 spin_lock(&journal->j_state_lock);
234 journal->j_flags |= JBD2_UNMOUNT;
236 while (journal->j_task) {
237 wake_up(&journal->j_wait_commit);
238 spin_unlock(&journal->j_state_lock);
239 wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
240 spin_lock(&journal->j_state_lock);
242 spin_unlock(&journal->j_state_lock);
246 * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
248 * Writes a metadata buffer to a given disk block. The actual IO is not
249 * performed but a new buffer_head is constructed which labels the data
250 * to be written with the correct destination disk block.
252 * Any magic-number escaping which needs to be done will cause a
253 * copy-out here. If the buffer happens to start with the
254 * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
255 * magic number is only written to the log for descripter blocks. In
256 * this case, we copy the data and replace the first word with 0, and we
257 * return a result code which indicates that this buffer needs to be
258 * marked as an escaped buffer in the corresponding log descriptor
259 * block. The missing word can then be restored when the block is read
262 * If the source buffer has already been modified by a new transaction
263 * since we took the last commit snapshot, we use the frozen copy of
264 * that data for IO. If we end up using the existing buffer_head's data
265 * for the write, then we *have* to lock the buffer to prevent anyone
266 * else from using and possibly modifying it while the IO is in
269 * The function returns a pointer to the buffer_heads to be used for IO.
271 * We assume that the journal has already been locked in this function.
278 * Bit 0 set == escape performed on the data
279 * Bit 1 set == buffer copy-out performed (kfree the data after IO)
282 int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
283 struct journal_head *jh_in,
284 struct journal_head **jh_out,
285 unsigned long long blocknr)
287 int need_copy_out = 0;
288 int done_copy_out = 0;
291 struct buffer_head *new_bh;
292 struct journal_head *new_jh;
293 struct page *new_page;
294 unsigned int new_offset;
295 struct buffer_head *bh_in = jh2bh(jh_in);
296 struct jbd2_buffer_trigger_type *triggers;
297 journal_t *journal = transaction->t_journal;
300 * The buffer really shouldn't be locked: only the current committing
301 * transaction is allowed to write it, so nobody else is allowed
304 * akpm: except if we're journalling data, and write() output is
305 * also part of a shared mapping, and another thread has
306 * decided to launch a writepage() against this buffer.
308 J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
310 new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
311 /* keep subsequent assertions sane */
313 init_buffer(new_bh, NULL, NULL);
314 atomic_set(&new_bh->b_count, 1);
315 new_jh = jbd2_journal_add_journal_head(new_bh); /* This sleeps */
318 * If a new transaction has already done a buffer copy-out, then
319 * we use that version of the data for the commit.
321 jbd_lock_bh_state(bh_in);
323 if (jh_in->b_frozen_data) {
325 new_page = virt_to_page(jh_in->b_frozen_data);
326 new_offset = offset_in_page(jh_in->b_frozen_data);
327 triggers = jh_in->b_frozen_triggers;
329 new_page = jh2bh(jh_in)->b_page;
330 new_offset = offset_in_page(jh2bh(jh_in)->b_data);
331 triggers = jh_in->b_triggers;
334 mapped_data = kmap_atomic(new_page, KM_USER0);
336 * Fire any commit trigger. Do this before checking for escaping,
337 * as the trigger may modify the magic offset. If a copy-out
338 * happens afterwards, it will have the correct data in the buffer.
340 jbd2_buffer_commit_trigger(jh_in, mapped_data + new_offset,
346 if (*((__be32 *)(mapped_data + new_offset)) ==
347 cpu_to_be32(JBD2_MAGIC_NUMBER)) {
351 kunmap_atomic(mapped_data, KM_USER0);
354 * Do we need to do a data copy?
356 if (need_copy_out && !done_copy_out) {
359 jbd_unlock_bh_state(bh_in);
360 tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
362 jbd2_journal_put_journal_head(new_jh);
365 jbd_lock_bh_state(bh_in);
366 if (jh_in->b_frozen_data) {
367 jbd2_free(tmp, bh_in->b_size);
371 jh_in->b_frozen_data = tmp;
372 mapped_data = kmap_atomic(new_page, KM_USER0);
373 memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size);
374 kunmap_atomic(mapped_data, KM_USER0);
376 new_page = virt_to_page(tmp);
377 new_offset = offset_in_page(tmp);
381 * This isn't strictly necessary, as we're using frozen
382 * data for the escaping, but it keeps consistency with
383 * b_frozen_data usage.
385 jh_in->b_frozen_triggers = jh_in->b_triggers;
389 * Did we need to do an escaping? Now we've done all the
390 * copying, we can finally do so.
393 mapped_data = kmap_atomic(new_page, KM_USER0);
394 *((unsigned int *)(mapped_data + new_offset)) = 0;
395 kunmap_atomic(mapped_data, KM_USER0);
398 set_bh_page(new_bh, new_page, new_offset);
399 new_jh->b_transaction = NULL;
400 new_bh->b_size = jh2bh(jh_in)->b_size;
401 new_bh->b_bdev = transaction->t_journal->j_dev;
402 new_bh->b_blocknr = blocknr;
403 set_buffer_mapped(new_bh);
404 set_buffer_dirty(new_bh);
409 * The to-be-written buffer needs to get moved to the io queue,
410 * and the original buffer whose contents we are shadowing or
411 * copying is moved to the transaction's shadow queue.
413 JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
414 spin_lock(&journal->j_list_lock);
415 __jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
416 spin_unlock(&journal->j_list_lock);
417 jbd_unlock_bh_state(bh_in);
419 JBUFFER_TRACE(new_jh, "file as BJ_IO");
420 jbd2_journal_file_buffer(new_jh, transaction, BJ_IO);
422 return do_escape | (done_copy_out << 1);
426 * Allocation code for the journal file. Manage the space left in the
427 * journal, so that we can begin checkpointing when appropriate.
431 * __jbd2_log_space_left: Return the number of free blocks left in the journal.
433 * Called with the journal already locked.
435 * Called under j_state_lock
438 int __jbd2_log_space_left(journal_t *journal)
440 int left = journal->j_free;
442 assert_spin_locked(&journal->j_state_lock);
445 * Be pessimistic here about the number of those free blocks which
446 * might be required for log descriptor control blocks.
449 #define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */
451 left -= MIN_LOG_RESERVED_BLOCKS;
460 * Called under j_state_lock. Returns true if a transaction commit was started.
462 int __jbd2_log_start_commit(journal_t *journal, tid_t target)
465 * Are we already doing a recent enough commit?
467 if (!tid_geq(journal->j_commit_request, target)) {
469 * We want a new commit: OK, mark the request and wakup the
470 * commit thread. We do _not_ do the commit ourselves.
473 journal->j_commit_request = target;
474 jbd_debug(1, "JBD: requesting commit %d/%d\n",
475 journal->j_commit_request,
476 journal->j_commit_sequence);
477 wake_up(&journal->j_wait_commit);
483 int jbd2_log_start_commit(journal_t *journal, tid_t tid)
487 spin_lock(&journal->j_state_lock);
488 ret = __jbd2_log_start_commit(journal, tid);
489 spin_unlock(&journal->j_state_lock);
494 * Force and wait upon a commit if the calling process is not within
495 * transaction. This is used for forcing out undo-protected data which contains
496 * bitmaps, when the fs is running out of space.
498 * We can only force the running transaction if we don't have an active handle;
499 * otherwise, we will deadlock.
501 * Returns true if a transaction was started.
503 int jbd2_journal_force_commit_nested(journal_t *journal)
505 transaction_t *transaction = NULL;
508 spin_lock(&journal->j_state_lock);
509 if (journal->j_running_transaction && !current->journal_info) {
510 transaction = journal->j_running_transaction;
511 __jbd2_log_start_commit(journal, transaction->t_tid);
512 } else if (journal->j_committing_transaction)
513 transaction = journal->j_committing_transaction;
516 spin_unlock(&journal->j_state_lock);
517 return 0; /* Nothing to retry */
520 tid = transaction->t_tid;
521 spin_unlock(&journal->j_state_lock);
522 jbd2_log_wait_commit(journal, tid);
527 * Start a commit of the current running transaction (if any). Returns true
528 * if a transaction is going to be committed (or is currently already
529 * committing), and fills its tid in at *ptid
531 int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
535 spin_lock(&journal->j_state_lock);
536 if (journal->j_running_transaction) {
537 tid_t tid = journal->j_running_transaction->t_tid;
539 __jbd2_log_start_commit(journal, tid);
540 /* There's a running transaction and we've just made sure
541 * it's commit has been scheduled. */
545 } else if (journal->j_committing_transaction) {
547 * If ext3_write_super() recently started a commit, then we
548 * have to wait for completion of that transaction
551 *ptid = journal->j_committing_transaction->t_tid;
554 spin_unlock(&journal->j_state_lock);
559 * Wait for a specified commit to complete.
560 * The caller may not hold the journal lock.
562 int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
566 #ifdef CONFIG_JBD2_DEBUG
567 spin_lock(&journal->j_state_lock);
568 if (!tid_geq(journal->j_commit_request, tid)) {
570 "%s: error: j_commit_request=%d, tid=%d\n",
571 __func__, journal->j_commit_request, tid);
573 spin_unlock(&journal->j_state_lock);
575 spin_lock(&journal->j_state_lock);
576 while (tid_gt(tid, journal->j_commit_sequence)) {
577 jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n",
578 tid, journal->j_commit_sequence);
579 wake_up(&journal->j_wait_commit);
580 spin_unlock(&journal->j_state_lock);
581 wait_event(journal->j_wait_done_commit,
582 !tid_gt(tid, journal->j_commit_sequence));
583 spin_lock(&journal->j_state_lock);
585 spin_unlock(&journal->j_state_lock);
587 if (unlikely(is_journal_aborted(journal))) {
588 printk(KERN_EMERG "journal commit I/O error\n");
595 * Log buffer allocation routines:
598 int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
600 unsigned long blocknr;
602 spin_lock(&journal->j_state_lock);
603 J_ASSERT(journal->j_free > 1);
605 blocknr = journal->j_head;
608 if (journal->j_head == journal->j_last)
609 journal->j_head = journal->j_first;
610 spin_unlock(&journal->j_state_lock);
611 return jbd2_journal_bmap(journal, blocknr, retp);
615 * Conversion of logical to physical block numbers for the journal
617 * On external journals the journal blocks are identity-mapped, so
618 * this is a no-op. If needed, we can use j_blk_offset - everything is
621 int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
622 unsigned long long *retp)
625 unsigned long long ret;
627 if (journal->j_inode) {
628 ret = bmap(journal->j_inode, blocknr);
632 printk(KERN_ALERT "%s: journal block not found "
633 "at offset %lu on %s\n",
634 __func__, blocknr, journal->j_devname);
636 __journal_abort_soft(journal, err);
639 *retp = blocknr; /* +journal->j_blk_offset */
645 * We play buffer_head aliasing tricks to write data/metadata blocks to
646 * the journal without copying their contents, but for journal
647 * descriptor blocks we do need to generate bona fide buffers.
649 * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
650 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
651 * But we don't bother doing that, so there will be coherency problems with
652 * mmaps of blockdevs which hold live JBD-controlled filesystems.
654 struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
656 struct buffer_head *bh;
657 unsigned long long blocknr;
660 err = jbd2_journal_next_log_block(journal, &blocknr);
665 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
669 memset(bh->b_data, 0, journal->j_blocksize);
670 set_buffer_uptodate(bh);
672 BUFFER_TRACE(bh, "return this buffer");
673 return jbd2_journal_add_journal_head(bh);
676 struct jbd2_stats_proc_session {
678 struct transaction_stats_s *stats;
683 static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
685 return *pos ? NULL : SEQ_START_TOKEN;
688 static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
693 static int jbd2_seq_info_show(struct seq_file *seq, void *v)
695 struct jbd2_stats_proc_session *s = seq->private;
697 if (v != SEQ_START_TOKEN)
699 seq_printf(seq, "%lu transaction, each up to %u blocks\n",
701 s->journal->j_max_transaction_buffers);
702 if (s->stats->ts_tid == 0)
704 seq_printf(seq, "average: \n %ums waiting for transaction\n",
705 jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
706 seq_printf(seq, " %ums running transaction\n",
707 jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
708 seq_printf(seq, " %ums transaction was being locked\n",
709 jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
710 seq_printf(seq, " %ums flushing data (in ordered mode)\n",
711 jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
712 seq_printf(seq, " %ums logging transaction\n",
713 jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
714 seq_printf(seq, " %lluus average transaction commit time\n",
715 div_u64(s->journal->j_average_commit_time, 1000));
716 seq_printf(seq, " %lu handles per transaction\n",
717 s->stats->run.rs_handle_count / s->stats->ts_tid);
718 seq_printf(seq, " %lu blocks per transaction\n",
719 s->stats->run.rs_blocks / s->stats->ts_tid);
720 seq_printf(seq, " %lu logged blocks per transaction\n",
721 s->stats->run.rs_blocks_logged / s->stats->ts_tid);
725 static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
729 static const struct seq_operations jbd2_seq_info_ops = {
730 .start = jbd2_seq_info_start,
731 .next = jbd2_seq_info_next,
732 .stop = jbd2_seq_info_stop,
733 .show = jbd2_seq_info_show,
736 static int jbd2_seq_info_open(struct inode *inode, struct file *file)
738 journal_t *journal = PDE(inode)->data;
739 struct jbd2_stats_proc_session *s;
742 s = kmalloc(sizeof(*s), GFP_KERNEL);
745 size = sizeof(struct transaction_stats_s);
746 s->stats = kmalloc(size, GFP_KERNEL);
747 if (s->stats == NULL) {
751 spin_lock(&journal->j_history_lock);
752 memcpy(s->stats, &journal->j_stats, size);
753 s->journal = journal;
754 spin_unlock(&journal->j_history_lock);
756 rc = seq_open(file, &jbd2_seq_info_ops);
758 struct seq_file *m = file->private_data;
768 static int jbd2_seq_info_release(struct inode *inode, struct file *file)
770 struct seq_file *seq = file->private_data;
771 struct jbd2_stats_proc_session *s = seq->private;
774 return seq_release(inode, file);
777 static const struct file_operations jbd2_seq_info_fops = {
778 .owner = THIS_MODULE,
779 .open = jbd2_seq_info_open,
782 .release = jbd2_seq_info_release,
785 static struct proc_dir_entry *proc_jbd2_stats;
787 static void jbd2_stats_proc_init(journal_t *journal)
789 journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
790 if (journal->j_proc_entry) {
791 proc_create_data("info", S_IRUGO, journal->j_proc_entry,
792 &jbd2_seq_info_fops, journal);
796 static void jbd2_stats_proc_exit(journal_t *journal)
798 remove_proc_entry("info", journal->j_proc_entry);
799 remove_proc_entry(journal->j_devname, proc_jbd2_stats);
803 * Management for journal control blocks: functions to create and
804 * destroy journal_t structures, and to initialise and read existing
805 * journal blocks from disk. */
807 /* First: create and setup a journal_t object in memory. We initialise
808 * very few fields yet: that has to wait until we have created the
809 * journal structures from from scratch, or loaded them from disk. */
811 static journal_t * journal_init_common (void)
816 journal = kzalloc(sizeof(*journal), GFP_KERNEL|__GFP_NOFAIL);
820 init_waitqueue_head(&journal->j_wait_transaction_locked);
821 init_waitqueue_head(&journal->j_wait_logspace);
822 init_waitqueue_head(&journal->j_wait_done_commit);
823 init_waitqueue_head(&journal->j_wait_checkpoint);
824 init_waitqueue_head(&journal->j_wait_commit);
825 init_waitqueue_head(&journal->j_wait_updates);
826 mutex_init(&journal->j_barrier);
827 mutex_init(&journal->j_checkpoint_mutex);
828 spin_lock_init(&journal->j_revoke_lock);
829 spin_lock_init(&journal->j_list_lock);
830 spin_lock_init(&journal->j_state_lock);
832 journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
833 journal->j_min_batch_time = 0;
834 journal->j_max_batch_time = 15000; /* 15ms */
836 /* The journal is marked for error until we succeed with recovery! */
837 journal->j_flags = JBD2_ABORT;
839 /* Set up a default-sized revoke table for the new mount. */
840 err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
846 spin_lock_init(&journal->j_history_lock);
853 /* jbd2_journal_init_dev and jbd2_journal_init_inode:
855 * Create a journal structure assigned some fixed set of disk blocks to
856 * the journal. We don't actually touch those disk blocks yet, but we
857 * need to set up all of the mapping information to tell the journaling
858 * system where the journal blocks are.
863 * journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
864 * @bdev: Block device on which to create the journal
865 * @fs_dev: Device which hold journalled filesystem for this journal.
866 * @start: Block nr Start of journal.
867 * @len: Length of the journal in blocks.
868 * @blocksize: blocksize of journalling device
870 * Returns: a newly created journal_t *
872 * jbd2_journal_init_dev creates a journal which maps a fixed contiguous
873 * range of blocks on an arbitrary block device.
876 journal_t * jbd2_journal_init_dev(struct block_device *bdev,
877 struct block_device *fs_dev,
878 unsigned long long start, int len, int blocksize)
880 journal_t *journal = journal_init_common();
881 struct buffer_head *bh;
888 /* journal descriptor can store up to n blocks -bzzz */
889 journal->j_blocksize = blocksize;
890 jbd2_stats_proc_init(journal);
891 n = journal->j_blocksize / sizeof(journal_block_tag_t);
892 journal->j_wbufsize = n;
893 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
894 if (!journal->j_wbuf) {
895 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
899 journal->j_dev = bdev;
900 journal->j_fs_dev = fs_dev;
901 journal->j_blk_offset = start;
902 journal->j_maxlen = len;
903 bdevname(journal->j_dev, journal->j_devname);
904 p = journal->j_devname;
905 while ((p = strchr(p, '/')))
908 bh = __getblk(journal->j_dev, start, journal->j_blocksize);
911 "%s: Cannot get buffer for journal superblock\n",
915 journal->j_sb_buffer = bh;
916 journal->j_superblock = (journal_superblock_t *)bh->b_data;
920 kfree(journal->j_wbuf);
921 jbd2_stats_proc_exit(journal);
927 * journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
928 * @inode: An inode to create the journal in
930 * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
931 * the journal. The inode must exist already, must support bmap() and
932 * must have all data blocks preallocated.
934 journal_t * jbd2_journal_init_inode (struct inode *inode)
936 struct buffer_head *bh;
937 journal_t *journal = journal_init_common();
941 unsigned long long blocknr;
946 journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
947 journal->j_inode = inode;
948 bdevname(journal->j_dev, journal->j_devname);
949 p = journal->j_devname;
950 while ((p = strchr(p, '/')))
952 p = journal->j_devname + strlen(journal->j_devname);
953 sprintf(p, "-%lu", journal->j_inode->i_ino);
955 "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
956 journal, inode->i_sb->s_id, inode->i_ino,
957 (long long) inode->i_size,
958 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
960 journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
961 journal->j_blocksize = inode->i_sb->s_blocksize;
962 jbd2_stats_proc_init(journal);
964 /* journal descriptor can store up to n blocks -bzzz */
965 n = journal->j_blocksize / sizeof(journal_block_tag_t);
966 journal->j_wbufsize = n;
967 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
968 if (!journal->j_wbuf) {
969 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
974 err = jbd2_journal_bmap(journal, 0, &blocknr);
975 /* If that failed, give up */
977 printk(KERN_ERR "%s: Cannnot locate journal superblock\n",
982 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
985 "%s: Cannot get buffer for journal superblock\n",
989 journal->j_sb_buffer = bh;
990 journal->j_superblock = (journal_superblock_t *)bh->b_data;
994 kfree(journal->j_wbuf);
995 jbd2_stats_proc_exit(journal);
1001 * If the journal init or create aborts, we need to mark the journal
1002 * superblock as being NULL to prevent the journal destroy from writing
1003 * back a bogus superblock.
1005 static void journal_fail_superblock (journal_t *journal)
1007 struct buffer_head *bh = journal->j_sb_buffer;
1009 journal->j_sb_buffer = NULL;
1013 * Given a journal_t structure, initialise the various fields for
1014 * startup of a new journaling session. We use this both when creating
1015 * a journal, and after recovering an old journal to reset it for
1019 static int journal_reset(journal_t *journal)
1021 journal_superblock_t *sb = journal->j_superblock;
1022 unsigned long long first, last;
1024 first = be32_to_cpu(sb->s_first);
1025 last = be32_to_cpu(sb->s_maxlen);
1026 if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
1027 printk(KERN_ERR "JBD: Journal too short (blocks %llu-%llu).\n",
1029 journal_fail_superblock(journal);
1033 journal->j_first = first;
1034 journal->j_last = last;
1036 journal->j_head = first;
1037 journal->j_tail = first;
1038 journal->j_free = last - first;
1040 journal->j_tail_sequence = journal->j_transaction_sequence;
1041 journal->j_commit_sequence = journal->j_transaction_sequence - 1;
1042 journal->j_commit_request = journal->j_commit_sequence;
1044 journal->j_max_transaction_buffers = journal->j_maxlen / 4;
1046 /* Add the dynamic fields and write it to disk. */
1047 jbd2_journal_update_superblock(journal, 1);
1048 return jbd2_journal_start_thread(journal);
1052 * void jbd2_journal_update_superblock() - Update journal sb on disk.
1053 * @journal: The journal to update.
1054 * @wait: Set to '0' if you don't want to wait for IO completion.
1056 * Update a journal's dynamic superblock fields and write it to disk,
1057 * optionally waiting for the IO to complete.
1059 void jbd2_journal_update_superblock(journal_t *journal, int wait)
1061 journal_superblock_t *sb = journal->j_superblock;
1062 struct buffer_head *bh = journal->j_sb_buffer;
1065 * As a special case, if the on-disk copy is already marked as needing
1066 * no recovery (s_start == 0) and there are no outstanding transactions
1067 * in the filesystem, then we can safely defer the superblock update
1068 * until the next commit by setting JBD2_FLUSHED. This avoids
1069 * attempting a write to a potential-readonly device.
1071 if (sb->s_start == 0 && journal->j_tail_sequence ==
1072 journal->j_transaction_sequence) {
1073 jbd_debug(1,"JBD: Skipping superblock update on recovered sb "
1074 "(start %ld, seq %d, errno %d)\n",
1075 journal->j_tail, journal->j_tail_sequence,
1080 if (buffer_write_io_error(bh)) {
1082 * Oh, dear. A previous attempt to write the journal
1083 * superblock failed. This could happen because the
1084 * USB device was yanked out. Or it could happen to
1085 * be a transient write error and maybe the block will
1086 * be remapped. Nothing we can do but to retry the
1087 * write and hope for the best.
1089 printk(KERN_ERR "JBD2: previous I/O error detected "
1090 "for journal superblock update for %s.\n",
1091 journal->j_devname);
1092 clear_buffer_write_io_error(bh);
1093 set_buffer_uptodate(bh);
1096 spin_lock(&journal->j_state_lock);
1097 jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n",
1098 journal->j_tail, journal->j_tail_sequence, journal->j_errno);
1100 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
1101 sb->s_start = cpu_to_be32(journal->j_tail);
1102 sb->s_errno = cpu_to_be32(journal->j_errno);
1103 spin_unlock(&journal->j_state_lock);
1105 BUFFER_TRACE(bh, "marking dirty");
1106 mark_buffer_dirty(bh);
1108 sync_dirty_buffer(bh);
1109 if (buffer_write_io_error(bh)) {
1110 printk(KERN_ERR "JBD2: I/O error detected "
1111 "when updating journal superblock for %s.\n",
1112 journal->j_devname);
1113 clear_buffer_write_io_error(bh);
1114 set_buffer_uptodate(bh);
1117 ll_rw_block(SWRITE, 1, &bh);
1120 /* If we have just flushed the log (by marking s_start==0), then
1121 * any future commit will have to be careful to update the
1122 * superblock again to re-record the true start of the log. */
1124 spin_lock(&journal->j_state_lock);
1126 journal->j_flags &= ~JBD2_FLUSHED;
1128 journal->j_flags |= JBD2_FLUSHED;
1129 spin_unlock(&journal->j_state_lock);
1133 * Read the superblock for a given journal, performing initial
1134 * validation of the format.
1137 static int journal_get_superblock(journal_t *journal)
1139 struct buffer_head *bh;
1140 journal_superblock_t *sb;
1143 bh = journal->j_sb_buffer;
1145 J_ASSERT(bh != NULL);
1146 if (!buffer_uptodate(bh)) {
1147 ll_rw_block(READ, 1, &bh);
1149 if (!buffer_uptodate(bh)) {
1151 "JBD: IO error reading journal superblock\n");
1156 sb = journal->j_superblock;
1160 if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1161 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1162 printk(KERN_WARNING "JBD: no valid journal superblock found\n");
1166 switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1167 case JBD2_SUPERBLOCK_V1:
1168 journal->j_format_version = 1;
1170 case JBD2_SUPERBLOCK_V2:
1171 journal->j_format_version = 2;
1174 printk(KERN_WARNING "JBD: unrecognised superblock format ID\n");
1178 if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
1179 journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
1180 else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
1181 printk (KERN_WARNING "JBD: journal file too short\n");
1188 journal_fail_superblock(journal);
1193 * Load the on-disk journal superblock and read the key fields into the
1197 static int load_superblock(journal_t *journal)
1200 journal_superblock_t *sb;
1202 err = journal_get_superblock(journal);
1206 sb = journal->j_superblock;
1208 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1209 journal->j_tail = be32_to_cpu(sb->s_start);
1210 journal->j_first = be32_to_cpu(sb->s_first);
1211 journal->j_last = be32_to_cpu(sb->s_maxlen);
1212 journal->j_errno = be32_to_cpu(sb->s_errno);
1219 * int jbd2_journal_load() - Read journal from disk.
1220 * @journal: Journal to act on.
1222 * Given a journal_t structure which tells us which disk blocks contain
1223 * a journal, read the journal from disk to initialise the in-memory
1226 int jbd2_journal_load(journal_t *journal)
1229 journal_superblock_t *sb;
1231 err = load_superblock(journal);
1235 sb = journal->j_superblock;
1236 /* If this is a V2 superblock, then we have to check the
1237 * features flags on it. */
1239 if (journal->j_format_version >= 2) {
1240 if ((sb->s_feature_ro_compat &
1241 ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
1242 (sb->s_feature_incompat &
1243 ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
1244 printk (KERN_WARNING
1245 "JBD: Unrecognised features on journal\n");
1250 /* Let the recovery code check whether it needs to recover any
1251 * data from the journal. */
1252 if (jbd2_journal_recover(journal))
1253 goto recovery_error;
1255 if (journal->j_failed_commit) {
1256 printk(KERN_ERR "JBD2: journal transaction %u on %s "
1257 "is corrupt.\n", journal->j_failed_commit,
1258 journal->j_devname);
1262 /* OK, we've finished with the dynamic journal bits:
1263 * reinitialise the dynamic contents of the superblock in memory
1264 * and reset them on disk. */
1265 if (journal_reset(journal))
1266 goto recovery_error;
1268 journal->j_flags &= ~JBD2_ABORT;
1269 journal->j_flags |= JBD2_LOADED;
1273 printk (KERN_WARNING "JBD: recovery failed\n");
1278 * void jbd2_journal_destroy() - Release a journal_t structure.
1279 * @journal: Journal to act on.
1281 * Release a journal_t structure once it is no longer in use by the
1283 * Return <0 if we couldn't clean up the journal.
1285 int jbd2_journal_destroy(journal_t *journal)
1289 /* Wait for the commit thread to wake up and die. */
1290 journal_kill_thread(journal);
1292 /* Force a final log commit */
1293 if (journal->j_running_transaction)
1294 jbd2_journal_commit_transaction(journal);
1296 /* Force any old transactions to disk */
1298 /* Totally anal locking here... */
1299 spin_lock(&journal->j_list_lock);
1300 while (journal->j_checkpoint_transactions != NULL) {
1301 spin_unlock(&journal->j_list_lock);
1302 mutex_lock(&journal->j_checkpoint_mutex);
1303 jbd2_log_do_checkpoint(journal);
1304 mutex_unlock(&journal->j_checkpoint_mutex);
1305 spin_lock(&journal->j_list_lock);
1308 J_ASSERT(journal->j_running_transaction == NULL);
1309 J_ASSERT(journal->j_committing_transaction == NULL);
1310 J_ASSERT(journal->j_checkpoint_transactions == NULL);
1311 spin_unlock(&journal->j_list_lock);
1313 if (journal->j_sb_buffer) {
1314 if (!is_journal_aborted(journal)) {
1315 /* We can now mark the journal as empty. */
1316 journal->j_tail = 0;
1317 journal->j_tail_sequence =
1318 ++journal->j_transaction_sequence;
1319 jbd2_journal_update_superblock(journal, 1);
1323 brelse(journal->j_sb_buffer);
1326 if (journal->j_proc_entry)
1327 jbd2_stats_proc_exit(journal);
1328 if (journal->j_inode)
1329 iput(journal->j_inode);
1330 if (journal->j_revoke)
1331 jbd2_journal_destroy_revoke(journal);
1332 kfree(journal->j_wbuf);
1340 *int jbd2_journal_check_used_features () - Check if features specified are used.
1341 * @journal: Journal to check.
1342 * @compat: bitmask of compatible features
1343 * @ro: bitmask of features that force read-only mount
1344 * @incompat: bitmask of incompatible features
1346 * Check whether the journal uses all of a given set of
1347 * features. Return true (non-zero) if it does.
1350 int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,
1351 unsigned long ro, unsigned long incompat)
1353 journal_superblock_t *sb;
1355 if (!compat && !ro && !incompat)
1357 if (journal->j_format_version == 1)
1360 sb = journal->j_superblock;
1362 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
1363 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
1364 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
1371 * int jbd2_journal_check_available_features() - Check feature set in journalling layer
1372 * @journal: Journal to check.
1373 * @compat: bitmask of compatible features
1374 * @ro: bitmask of features that force read-only mount
1375 * @incompat: bitmask of incompatible features
1377 * Check whether the journaling code supports the use of
1378 * all of a given set of features on this journal. Return true
1379 * (non-zero) if it can. */
1381 int jbd2_journal_check_available_features (journal_t *journal, unsigned long compat,
1382 unsigned long ro, unsigned long incompat)
1384 journal_superblock_t *sb;
1386 if (!compat && !ro && !incompat)
1389 sb = journal->j_superblock;
1391 /* We can support any known requested features iff the
1392 * superblock is in version 2. Otherwise we fail to support any
1393 * extended sb features. */
1395 if (journal->j_format_version != 2)
1398 if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
1399 (ro & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
1400 (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
1407 * int jbd2_journal_set_features () - Mark a given journal feature in the superblock
1408 * @journal: Journal to act on.
1409 * @compat: bitmask of compatible features
1410 * @ro: bitmask of features that force read-only mount
1411 * @incompat: bitmask of incompatible features
1413 * Mark a given journal feature as present on the
1414 * superblock. Returns true if the requested features could be set.
1418 int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
1419 unsigned long ro, unsigned long incompat)
1421 journal_superblock_t *sb;
1423 if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
1426 if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
1429 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1430 compat, ro, incompat);
1432 sb = journal->j_superblock;
1434 sb->s_feature_compat |= cpu_to_be32(compat);
1435 sb->s_feature_ro_compat |= cpu_to_be32(ro);
1436 sb->s_feature_incompat |= cpu_to_be32(incompat);
1442 * jbd2_journal_clear_features () - Clear a given journal feature in the
1444 * @journal: Journal to act on.
1445 * @compat: bitmask of compatible features
1446 * @ro: bitmask of features that force read-only mount
1447 * @incompat: bitmask of incompatible features
1449 * Clear a given journal feature as present on the
1452 void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
1453 unsigned long ro, unsigned long incompat)
1455 journal_superblock_t *sb;
1457 jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
1458 compat, ro, incompat);
1460 sb = journal->j_superblock;
1462 sb->s_feature_compat &= ~cpu_to_be32(compat);
1463 sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
1464 sb->s_feature_incompat &= ~cpu_to_be32(incompat);
1466 EXPORT_SYMBOL(jbd2_journal_clear_features);
1469 * int jbd2_journal_update_format () - Update on-disk journal structure.
1470 * @journal: Journal to act on.
1472 * Given an initialised but unloaded journal struct, poke about in the
1473 * on-disk structure to update it to the most recent supported version.
1475 int jbd2_journal_update_format (journal_t *journal)
1477 journal_superblock_t *sb;
1480 err = journal_get_superblock(journal);
1484 sb = journal->j_superblock;
1486 switch (be32_to_cpu(sb->s_header.h_blocktype)) {
1487 case JBD2_SUPERBLOCK_V2:
1489 case JBD2_SUPERBLOCK_V1:
1490 return journal_convert_superblock_v1(journal, sb);
1497 static int journal_convert_superblock_v1(journal_t *journal,
1498 journal_superblock_t *sb)
1500 int offset, blocksize;
1501 struct buffer_head *bh;
1504 "JBD: Converting superblock from version 1 to 2.\n");
1506 /* Pre-initialise new fields to zero */
1507 offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
1508 blocksize = be32_to_cpu(sb->s_blocksize);
1509 memset(&sb->s_feature_compat, 0, blocksize-offset);
1511 sb->s_nr_users = cpu_to_be32(1);
1512 sb->s_header.h_blocktype = cpu_to_be32(JBD2_SUPERBLOCK_V2);
1513 journal->j_format_version = 2;
1515 bh = journal->j_sb_buffer;
1516 BUFFER_TRACE(bh, "marking dirty");
1517 mark_buffer_dirty(bh);
1518 sync_dirty_buffer(bh);
1524 * int jbd2_journal_flush () - Flush journal
1525 * @journal: Journal to act on.
1527 * Flush all data for a given journal to disk and empty the journal.
1528 * Filesystems can use this when remounting readonly to ensure that
1529 * recovery does not need to happen on remount.
1532 int jbd2_journal_flush(journal_t *journal)
1535 transaction_t *transaction = NULL;
1536 unsigned long old_tail;
1538 spin_lock(&journal->j_state_lock);
1540 /* Force everything buffered to the log... */
1541 if (journal->j_running_transaction) {
1542 transaction = journal->j_running_transaction;
1543 __jbd2_log_start_commit(journal, transaction->t_tid);
1544 } else if (journal->j_committing_transaction)
1545 transaction = journal->j_committing_transaction;
1547 /* Wait for the log commit to complete... */
1549 tid_t tid = transaction->t_tid;
1551 spin_unlock(&journal->j_state_lock);
1552 jbd2_log_wait_commit(journal, tid);
1554 spin_unlock(&journal->j_state_lock);
1557 /* ...and flush everything in the log out to disk. */
1558 spin_lock(&journal->j_list_lock);
1559 while (!err && journal->j_checkpoint_transactions != NULL) {
1560 spin_unlock(&journal->j_list_lock);
1561 mutex_lock(&journal->j_checkpoint_mutex);
1562 err = jbd2_log_do_checkpoint(journal);
1563 mutex_unlock(&journal->j_checkpoint_mutex);
1564 spin_lock(&journal->j_list_lock);
1566 spin_unlock(&journal->j_list_lock);
1568 if (is_journal_aborted(journal))
1571 jbd2_cleanup_journal_tail(journal);
1573 /* Finally, mark the journal as really needing no recovery.
1574 * This sets s_start==0 in the underlying superblock, which is
1575 * the magic code for a fully-recovered superblock. Any future
1576 * commits of data to the journal will restore the current
1578 spin_lock(&journal->j_state_lock);
1579 old_tail = journal->j_tail;
1580 journal->j_tail = 0;
1581 spin_unlock(&journal->j_state_lock);
1582 jbd2_journal_update_superblock(journal, 1);
1583 spin_lock(&journal->j_state_lock);
1584 journal->j_tail = old_tail;
1586 J_ASSERT(!journal->j_running_transaction);
1587 J_ASSERT(!journal->j_committing_transaction);
1588 J_ASSERT(!journal->j_checkpoint_transactions);
1589 J_ASSERT(journal->j_head == journal->j_tail);
1590 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
1591 spin_unlock(&journal->j_state_lock);
1596 * int jbd2_journal_wipe() - Wipe journal contents
1597 * @journal: Journal to act on.
1598 * @write: flag (see below)
1600 * Wipe out all of the contents of a journal, safely. This will produce
1601 * a warning if the journal contains any valid recovery information.
1602 * Must be called between journal_init_*() and jbd2_journal_load().
1604 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
1605 * we merely suppress recovery.
1608 int jbd2_journal_wipe(journal_t *journal, int write)
1610 journal_superblock_t *sb;
1613 J_ASSERT (!(journal->j_flags & JBD2_LOADED));
1615 err = load_superblock(journal);
1619 sb = journal->j_superblock;
1621 if (!journal->j_tail)
1624 printk (KERN_WARNING "JBD: %s recovery information on journal\n",
1625 write ? "Clearing" : "Ignoring");
1627 err = jbd2_journal_skip_recovery(journal);
1629 jbd2_journal_update_superblock(journal, 1);
1636 * Journal abort has very specific semantics, which we describe
1637 * for journal abort.
1639 * Two internal functions, which provide abort to the jbd layer
1644 * Quick version for internal journal use (doesn't lock the journal).
1645 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
1646 * and don't attempt to make any other journal updates.
1648 void __jbd2_journal_abort_hard(journal_t *journal)
1650 transaction_t *transaction;
1652 if (journal->j_flags & JBD2_ABORT)
1655 printk(KERN_ERR "Aborting journal on device %s.\n",
1656 journal->j_devname);
1658 spin_lock(&journal->j_state_lock);
1659 journal->j_flags |= JBD2_ABORT;
1660 transaction = journal->j_running_transaction;
1662 __jbd2_log_start_commit(journal, transaction->t_tid);
1663 spin_unlock(&journal->j_state_lock);
1666 /* Soft abort: record the abort error status in the journal superblock,
1667 * but don't do any other IO. */
1668 static void __journal_abort_soft (journal_t *journal, int errno)
1670 if (journal->j_flags & JBD2_ABORT)
1673 if (!journal->j_errno)
1674 journal->j_errno = errno;
1676 __jbd2_journal_abort_hard(journal);
1679 jbd2_journal_update_superblock(journal, 1);
1683 * void jbd2_journal_abort () - Shutdown the journal immediately.
1684 * @journal: the journal to shutdown.
1685 * @errno: an error number to record in the journal indicating
1686 * the reason for the shutdown.
1688 * Perform a complete, immediate shutdown of the ENTIRE
1689 * journal (not of a single transaction). This operation cannot be
1690 * undone without closing and reopening the journal.
1692 * The jbd2_journal_abort function is intended to support higher level error
1693 * recovery mechanisms such as the ext2/ext3 remount-readonly error
1696 * Journal abort has very specific semantics. Any existing dirty,
1697 * unjournaled buffers in the main filesystem will still be written to
1698 * disk by bdflush, but the journaling mechanism will be suspended
1699 * immediately and no further transaction commits will be honoured.
1701 * Any dirty, journaled buffers will be written back to disk without
1702 * hitting the journal. Atomicity cannot be guaranteed on an aborted
1703 * filesystem, but we _do_ attempt to leave as much data as possible
1704 * behind for fsck to use for cleanup.
1706 * Any attempt to get a new transaction handle on a journal which is in
1707 * ABORT state will just result in an -EROFS error return. A
1708 * jbd2_journal_stop on an existing handle will return -EIO if we have
1709 * entered abort state during the update.
1711 * Recursive transactions are not disturbed by journal abort until the
1712 * final jbd2_journal_stop, which will receive the -EIO error.
1714 * Finally, the jbd2_journal_abort call allows the caller to supply an errno
1715 * which will be recorded (if possible) in the journal superblock. This
1716 * allows a client to record failure conditions in the middle of a
1717 * transaction without having to complete the transaction to record the
1718 * failure to disk. ext3_error, for example, now uses this
1721 * Errors which originate from within the journaling layer will NOT
1722 * supply an errno; a null errno implies that absolutely no further
1723 * writes are done to the journal (unless there are any already in
1728 void jbd2_journal_abort(journal_t *journal, int errno)
1730 __journal_abort_soft(journal, errno);
1734 * int jbd2_journal_errno () - returns the journal's error state.
1735 * @journal: journal to examine.
1737 * This is the errno number set with jbd2_journal_abort(), the last
1738 * time the journal was mounted - if the journal was stopped
1739 * without calling abort this will be 0.
1741 * If the journal has been aborted on this mount time -EROFS will
1744 int jbd2_journal_errno(journal_t *journal)
1748 spin_lock(&journal->j_state_lock);
1749 if (journal->j_flags & JBD2_ABORT)
1752 err = journal->j_errno;
1753 spin_unlock(&journal->j_state_lock);
1758 * int jbd2_journal_clear_err () - clears the journal's error state
1759 * @journal: journal to act on.
1761 * An error must be cleared or acked to take a FS out of readonly
1764 int jbd2_journal_clear_err(journal_t *journal)
1768 spin_lock(&journal->j_state_lock);
1769 if (journal->j_flags & JBD2_ABORT)
1772 journal->j_errno = 0;
1773 spin_unlock(&journal->j_state_lock);
1778 * void jbd2_journal_ack_err() - Ack journal err.
1779 * @journal: journal to act on.
1781 * An error must be cleared or acked to take a FS out of readonly
1784 void jbd2_journal_ack_err(journal_t *journal)
1786 spin_lock(&journal->j_state_lock);
1787 if (journal->j_errno)
1788 journal->j_flags |= JBD2_ACK_ERR;
1789 spin_unlock(&journal->j_state_lock);
1792 int jbd2_journal_blocks_per_page(struct inode *inode)
1794 return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
1798 * helper functions to deal with 32 or 64bit block numbers.
1800 size_t journal_tag_bytes(journal_t *journal)
1802 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
1803 return JBD2_TAG_SIZE64;
1805 return JBD2_TAG_SIZE32;
1809 * Journal_head storage management
1811 static struct kmem_cache *jbd2_journal_head_cache;
1812 #ifdef CONFIG_JBD2_DEBUG
1813 static atomic_t nr_journal_heads = ATOMIC_INIT(0);
1816 static int journal_init_jbd2_journal_head_cache(void)
1820 J_ASSERT(jbd2_journal_head_cache == NULL);
1821 jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
1822 sizeof(struct journal_head),
1824 SLAB_TEMPORARY, /* flags */
1827 if (!jbd2_journal_head_cache) {
1829 printk(KERN_EMERG "JBD: no memory for journal_head cache\n");
1834 static void jbd2_journal_destroy_jbd2_journal_head_cache(void)
1836 if (jbd2_journal_head_cache) {
1837 kmem_cache_destroy(jbd2_journal_head_cache);
1838 jbd2_journal_head_cache = NULL;
1843 * journal_head splicing and dicing
1845 static struct journal_head *journal_alloc_journal_head(void)
1847 struct journal_head *ret;
1848 static unsigned long last_warning;
1850 #ifdef CONFIG_JBD2_DEBUG
1851 atomic_inc(&nr_journal_heads);
1853 ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS);
1855 jbd_debug(1, "out of memory for journal_head\n");
1856 if (time_after(jiffies, last_warning + 5*HZ)) {
1857 printk(KERN_NOTICE "ENOMEM in %s, retrying.\n",
1859 last_warning = jiffies;
1863 ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS);
1869 static void journal_free_journal_head(struct journal_head *jh)
1871 #ifdef CONFIG_JBD2_DEBUG
1872 atomic_dec(&nr_journal_heads);
1873 memset(jh, JBD2_POISON_FREE, sizeof(*jh));
1875 kmem_cache_free(jbd2_journal_head_cache, jh);
1879 * A journal_head is attached to a buffer_head whenever JBD has an
1880 * interest in the buffer.
1882 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
1883 * is set. This bit is tested in core kernel code where we need to take
1884 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
1887 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
1889 * When a buffer has its BH_JBD bit set it is immune from being released by
1890 * core kernel code, mainly via ->b_count.
1892 * A journal_head may be detached from its buffer_head when the journal_head's
1893 * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL.
1894 * Various places in JBD call jbd2_journal_remove_journal_head() to indicate that the
1895 * journal_head can be dropped if needed.
1897 * Various places in the kernel want to attach a journal_head to a buffer_head
1898 * _before_ attaching the journal_head to a transaction. To protect the
1899 * journal_head in this situation, jbd2_journal_add_journal_head elevates the
1900 * journal_head's b_jcount refcount by one. The caller must call
1901 * jbd2_journal_put_journal_head() to undo this.
1903 * So the typical usage would be:
1905 * (Attach a journal_head if needed. Increments b_jcount)
1906 * struct journal_head *jh = jbd2_journal_add_journal_head(bh);
1908 * jh->b_transaction = xxx;
1909 * jbd2_journal_put_journal_head(jh);
1911 * Now, the journal_head's b_jcount is zero, but it is safe from being released
1912 * because it has a non-zero b_transaction.
1916 * Give a buffer_head a journal_head.
1918 * Doesn't need the journal lock.
1921 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
1923 struct journal_head *jh;
1924 struct journal_head *new_jh = NULL;
1927 if (!buffer_jbd(bh)) {
1928 new_jh = journal_alloc_journal_head();
1929 memset(new_jh, 0, sizeof(*new_jh));
1932 jbd_lock_bh_journal_head(bh);
1933 if (buffer_jbd(bh)) {
1937 (atomic_read(&bh->b_count) > 0) ||
1938 (bh->b_page && bh->b_page->mapping));
1941 jbd_unlock_bh_journal_head(bh);
1946 new_jh = NULL; /* We consumed it */
1951 BUFFER_TRACE(bh, "added journal_head");
1954 jbd_unlock_bh_journal_head(bh);
1956 journal_free_journal_head(new_jh);
1957 return bh->b_private;
1961 * Grab a ref against this buffer_head's journal_head. If it ended up not
1962 * having a journal_head, return NULL
1964 struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
1966 struct journal_head *jh = NULL;
1968 jbd_lock_bh_journal_head(bh);
1969 if (buffer_jbd(bh)) {
1973 jbd_unlock_bh_journal_head(bh);
1977 static void __journal_remove_journal_head(struct buffer_head *bh)
1979 struct journal_head *jh = bh2jh(bh);
1981 J_ASSERT_JH(jh, jh->b_jcount >= 0);
1984 if (jh->b_jcount == 0) {
1985 if (jh->b_transaction == NULL &&
1986 jh->b_next_transaction == NULL &&
1987 jh->b_cp_transaction == NULL) {
1988 J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
1989 J_ASSERT_BH(bh, buffer_jbd(bh));
1990 J_ASSERT_BH(bh, jh2bh(jh) == bh);
1991 BUFFER_TRACE(bh, "remove journal_head");
1992 if (jh->b_frozen_data) {
1993 printk(KERN_WARNING "%s: freeing "
1996 jbd2_free(jh->b_frozen_data, bh->b_size);
1998 if (jh->b_committed_data) {
1999 printk(KERN_WARNING "%s: freeing "
2000 "b_committed_data\n",
2002 jbd2_free(jh->b_committed_data, bh->b_size);
2004 bh->b_private = NULL;
2005 jh->b_bh = NULL; /* debug, really */
2006 clear_buffer_jbd(bh);
2008 journal_free_journal_head(jh);
2010 BUFFER_TRACE(bh, "journal_head was locked");
2016 * jbd2_journal_remove_journal_head(): if the buffer isn't attached to a transaction
2017 * and has a zero b_jcount then remove and release its journal_head. If we did
2018 * see that the buffer is not used by any transaction we also "logically"
2019 * decrement ->b_count.
2021 * We in fact take an additional increment on ->b_count as a convenience,
2022 * because the caller usually wants to do additional things with the bh
2023 * after calling here.
2024 * The caller of jbd2_journal_remove_journal_head() *must* run __brelse(bh) at some
2025 * time. Once the caller has run __brelse(), the buffer is eligible for
2026 * reaping by try_to_free_buffers().
2028 void jbd2_journal_remove_journal_head(struct buffer_head *bh)
2030 jbd_lock_bh_journal_head(bh);
2031 __journal_remove_journal_head(bh);
2032 jbd_unlock_bh_journal_head(bh);
2036 * Drop a reference on the passed journal_head. If it fell to zero then try to
2037 * release the journal_head from the buffer_head.
2039 void jbd2_journal_put_journal_head(struct journal_head *jh)
2041 struct buffer_head *bh = jh2bh(jh);
2043 jbd_lock_bh_journal_head(bh);
2044 J_ASSERT_JH(jh, jh->b_jcount > 0);
2046 if (!jh->b_jcount && !jh->b_transaction) {
2047 __journal_remove_journal_head(bh);
2050 jbd_unlock_bh_journal_head(bh);
2054 * Initialize jbd inode head
2056 void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
2058 jinode->i_transaction = NULL;
2059 jinode->i_next_transaction = NULL;
2060 jinode->i_vfs_inode = inode;
2061 jinode->i_flags = 0;
2062 INIT_LIST_HEAD(&jinode->i_list);
2066 * Function to be called before we start removing inode from memory (i.e.,
2067 * clear_inode() is a fine place to be called from). It removes inode from
2068 * transaction's lists.
2070 void jbd2_journal_release_jbd_inode(journal_t *journal,
2071 struct jbd2_inode *jinode)
2078 spin_lock(&journal->j_list_lock);
2079 /* Is commit writing out inode - we have to wait */
2080 if (jinode->i_flags & JI_COMMIT_RUNNING) {
2081 wait_queue_head_t *wq;
2082 DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
2083 wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
2084 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
2085 spin_unlock(&journal->j_list_lock);
2087 finish_wait(wq, &wait.wait);
2091 /* Do we need to wait for data writeback? */
2092 if (journal->j_committing_transaction == jinode->i_transaction)
2094 if (jinode->i_transaction) {
2095 list_del(&jinode->i_list);
2096 jinode->i_transaction = NULL;
2098 spin_unlock(&journal->j_list_lock);
2104 #ifdef CONFIG_JBD2_DEBUG
2105 u8 jbd2_journal_enable_debug __read_mostly;
2106 EXPORT_SYMBOL(jbd2_journal_enable_debug);
2108 #define JBD2_DEBUG_NAME "jbd2-debug"
2110 static struct dentry *jbd2_debugfs_dir;
2111 static struct dentry *jbd2_debug;
2113 static void __init jbd2_create_debugfs_entry(void)
2115 jbd2_debugfs_dir = debugfs_create_dir("jbd2", NULL);
2116 if (jbd2_debugfs_dir)
2117 jbd2_debug = debugfs_create_u8(JBD2_DEBUG_NAME, S_IRUGO,
2119 &jbd2_journal_enable_debug);
2122 static void __exit jbd2_remove_debugfs_entry(void)
2124 debugfs_remove(jbd2_debug);
2125 debugfs_remove(jbd2_debugfs_dir);
2130 static void __init jbd2_create_debugfs_entry(void)
2134 static void __exit jbd2_remove_debugfs_entry(void)
2140 #ifdef CONFIG_PROC_FS
2142 #define JBD2_STATS_PROC_NAME "fs/jbd2"
2144 static void __init jbd2_create_jbd_stats_proc_entry(void)
2146 proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
2149 static void __exit jbd2_remove_jbd_stats_proc_entry(void)
2151 if (proc_jbd2_stats)
2152 remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
2157 #define jbd2_create_jbd_stats_proc_entry() do {} while (0)
2158 #define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
2162 struct kmem_cache *jbd2_handle_cache;
2164 static int __init journal_init_handle_cache(void)
2166 jbd2_handle_cache = kmem_cache_create("jbd2_journal_handle",
2169 SLAB_TEMPORARY, /* flags */
2171 if (jbd2_handle_cache == NULL) {
2172 printk(KERN_EMERG "JBD: failed to create handle cache\n");
2178 static void jbd2_journal_destroy_handle_cache(void)
2180 if (jbd2_handle_cache)
2181 kmem_cache_destroy(jbd2_handle_cache);
2185 * Module startup and shutdown
2188 static int __init journal_init_caches(void)
2192 ret = jbd2_journal_init_revoke_caches();
2194 ret = journal_init_jbd2_journal_head_cache();
2196 ret = journal_init_handle_cache();
2200 static void jbd2_journal_destroy_caches(void)
2202 jbd2_journal_destroy_revoke_caches();
2203 jbd2_journal_destroy_jbd2_journal_head_cache();
2204 jbd2_journal_destroy_handle_cache();
2207 static int __init journal_init(void)
2211 BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
2213 ret = journal_init_caches();
2215 jbd2_create_debugfs_entry();
2216 jbd2_create_jbd_stats_proc_entry();
2218 jbd2_journal_destroy_caches();
2223 static void __exit journal_exit(void)
2225 #ifdef CONFIG_JBD2_DEBUG
2226 int n = atomic_read(&nr_journal_heads);
2228 printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n);
2230 jbd2_remove_debugfs_entry();
2231 jbd2_remove_jbd_stats_proc_entry();
2232 jbd2_journal_destroy_caches();
2236 * jbd2_dev_to_name is a utility function used by the jbd2 and ext4
2237 * tracing infrastructure to map a dev_t to a device name.
2239 * The caller should use rcu_read_lock() in order to make sure the
2240 * device name stays valid until its done with it. We use
2241 * rcu_read_lock() as well to make sure we're safe in case the caller
2242 * gets sloppy, and because rcu_read_lock() is cheap and can be safely
2245 struct devname_cache {
2246 struct rcu_head rcu;
2248 char devname[BDEVNAME_SIZE];
2250 #define CACHE_SIZE_BITS 6
2251 static struct devname_cache *devcache[1 << CACHE_SIZE_BITS];
2252 static DEFINE_SPINLOCK(devname_cache_lock);
2254 static void free_devcache(struct rcu_head *rcu)
2259 const char *jbd2_dev_to_name(dev_t device)
2261 int i = hash_32(device, CACHE_SIZE_BITS);
2263 struct block_device *bd;
2264 static struct devname_cache *new_dev;
2267 if (devcache[i] && devcache[i]->device == device) {
2268 ret = devcache[i]->devname;
2274 new_dev = kmalloc(sizeof(struct devname_cache), GFP_KERNEL);
2276 return "NODEV-ALLOCFAILURE"; /* Something non-NULL */
2277 spin_lock(&devname_cache_lock);
2279 if (devcache[i]->device == device) {
2281 ret = devcache[i]->devname;
2282 spin_unlock(&devname_cache_lock);
2285 call_rcu(&devcache[i]->rcu, free_devcache);
2287 devcache[i] = new_dev;
2288 devcache[i]->device = device;
2291 bdevname(bd, devcache[i]->devname);
2294 __bdevname(device, devcache[i]->devname);
2295 ret = devcache[i]->devname;
2296 spin_unlock(&devname_cache_lock);
2299 EXPORT_SYMBOL(jbd2_dev_to_name);
2301 MODULE_LICENSE("GPL");
2302 module_init(journal_init);
2303 module_exit(journal_exit);