[PATCH] net: Kill some unneeded allocation return value casts in libertas
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / jbd2 / journal.c
blobf37324aee817c9181fee667ba334c9df293f8666
1 /*
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
13 * journaling system.
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>
27 #include <linux/fs.h>
28 #include <linux/jbd2.h>
29 #include <linux/errno.h>
30 #include <linux/slab.h>
31 #include <linux/init.h>
32 #include <linux/mm.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>
40 #include <asm/uaccess.h>
41 #include <asm/page.h>
43 EXPORT_SYMBOL(jbd2_journal_start);
44 EXPORT_SYMBOL(jbd2_journal_restart);
45 EXPORT_SYMBOL(jbd2_journal_extend);
46 EXPORT_SYMBOL(jbd2_journal_stop);
47 EXPORT_SYMBOL(jbd2_journal_lock_updates);
48 EXPORT_SYMBOL(jbd2_journal_unlock_updates);
49 EXPORT_SYMBOL(jbd2_journal_get_write_access);
50 EXPORT_SYMBOL(jbd2_journal_get_create_access);
51 EXPORT_SYMBOL(jbd2_journal_get_undo_access);
52 EXPORT_SYMBOL(jbd2_journal_dirty_data);
53 EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
54 EXPORT_SYMBOL(jbd2_journal_release_buffer);
55 EXPORT_SYMBOL(jbd2_journal_forget);
56 #if 0
57 EXPORT_SYMBOL(journal_sync_buffer);
58 #endif
59 EXPORT_SYMBOL(jbd2_journal_flush);
60 EXPORT_SYMBOL(jbd2_journal_revoke);
62 EXPORT_SYMBOL(jbd2_journal_init_dev);
63 EXPORT_SYMBOL(jbd2_journal_init_inode);
64 EXPORT_SYMBOL(jbd2_journal_update_format);
65 EXPORT_SYMBOL(jbd2_journal_check_used_features);
66 EXPORT_SYMBOL(jbd2_journal_check_available_features);
67 EXPORT_SYMBOL(jbd2_journal_set_features);
68 EXPORT_SYMBOL(jbd2_journal_create);
69 EXPORT_SYMBOL(jbd2_journal_load);
70 EXPORT_SYMBOL(jbd2_journal_destroy);
71 EXPORT_SYMBOL(jbd2_journal_update_superblock);
72 EXPORT_SYMBOL(jbd2_journal_abort);
73 EXPORT_SYMBOL(jbd2_journal_errno);
74 EXPORT_SYMBOL(jbd2_journal_ack_err);
75 EXPORT_SYMBOL(jbd2_journal_clear_err);
76 EXPORT_SYMBOL(jbd2_log_wait_commit);
77 EXPORT_SYMBOL(jbd2_journal_start_commit);
78 EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
79 EXPORT_SYMBOL(jbd2_journal_wipe);
80 EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
81 EXPORT_SYMBOL(jbd2_journal_invalidatepage);
82 EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
83 EXPORT_SYMBOL(jbd2_journal_force_commit);
85 static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
86 static void __journal_abort_soft (journal_t *journal, int errno);
87 static int jbd2_journal_create_jbd_slab(size_t slab_size);
90 * Helper function used to manage commit timeouts
93 static void commit_timeout(unsigned long __data)
95 struct task_struct * p = (struct task_struct *) __data;
97 wake_up_process(p);
101 * kjournald2: The main thread function used to manage a logging device
102 * journal.
104 * This kernel thread is responsible for two things:
106 * 1) COMMIT: Every so often we need to commit the current state of the
107 * filesystem to disk. The journal thread is responsible for writing
108 * all of the metadata buffers to disk.
110 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
111 * of the data in that part of the log has been rewritten elsewhere on
112 * the disk. Flushing these old buffers to reclaim space in the log is
113 * known as checkpointing, and this thread is responsible for that job.
116 static int kjournald2(void *arg)
118 journal_t *journal = arg;
119 transaction_t *transaction;
122 * Set up an interval timer which can be used to trigger a commit wakeup
123 * after the commit interval expires
125 setup_timer(&journal->j_commit_timer, commit_timeout,
126 (unsigned long)current);
128 /* Record that the journal thread is running */
129 journal->j_task = current;
130 wake_up(&journal->j_wait_done_commit);
132 printk(KERN_INFO "kjournald2 starting. Commit interval %ld seconds\n",
133 journal->j_commit_interval / HZ);
136 * And now, wait forever for commit wakeup events.
138 spin_lock(&journal->j_state_lock);
140 loop:
141 if (journal->j_flags & JBD2_UNMOUNT)
142 goto end_loop;
144 jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
145 journal->j_commit_sequence, journal->j_commit_request);
147 if (journal->j_commit_sequence != journal->j_commit_request) {
148 jbd_debug(1, "OK, requests differ\n");
149 spin_unlock(&journal->j_state_lock);
150 del_timer_sync(&journal->j_commit_timer);
151 jbd2_journal_commit_transaction(journal);
152 spin_lock(&journal->j_state_lock);
153 goto loop;
156 wake_up(&journal->j_wait_done_commit);
157 if (freezing(current)) {
159 * The simpler the better. Flushing journal isn't a
160 * good idea, because that depends on threads that may
161 * be already stopped.
163 jbd_debug(1, "Now suspending kjournald2\n");
164 spin_unlock(&journal->j_state_lock);
165 refrigerator();
166 spin_lock(&journal->j_state_lock);
167 } else {
169 * We assume on resume that commits are already there,
170 * so we don't sleep
172 DEFINE_WAIT(wait);
173 int should_sleep = 1;
175 prepare_to_wait(&journal->j_wait_commit, &wait,
176 TASK_INTERRUPTIBLE);
177 if (journal->j_commit_sequence != journal->j_commit_request)
178 should_sleep = 0;
179 transaction = journal->j_running_transaction;
180 if (transaction && time_after_eq(jiffies,
181 transaction->t_expires))
182 should_sleep = 0;
183 if (journal->j_flags & JBD2_UNMOUNT)
184 should_sleep = 0;
185 if (should_sleep) {
186 spin_unlock(&journal->j_state_lock);
187 schedule();
188 spin_lock(&journal->j_state_lock);
190 finish_wait(&journal->j_wait_commit, &wait);
193 jbd_debug(1, "kjournald2 wakes\n");
196 * Were we woken up by a commit wakeup event?
198 transaction = journal->j_running_transaction;
199 if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
200 journal->j_commit_request = transaction->t_tid;
201 jbd_debug(1, "woke because of timeout\n");
203 goto loop;
205 end_loop:
206 spin_unlock(&journal->j_state_lock);
207 del_timer_sync(&journal->j_commit_timer);
208 journal->j_task = NULL;
209 wake_up(&journal->j_wait_done_commit);
210 jbd_debug(1, "Journal thread exiting.\n");
211 return 0;
214 static int jbd2_journal_start_thread(journal_t *journal)
216 struct task_struct *t;
218 t = kthread_run(kjournald2, journal, "kjournald2");
219 if (IS_ERR(t))
220 return PTR_ERR(t);
222 wait_event(journal->j_wait_done_commit, journal->j_task != 0);
223 return 0;
226 static void journal_kill_thread(journal_t *journal)
228 spin_lock(&journal->j_state_lock);
229 journal->j_flags |= JBD2_UNMOUNT;
231 while (journal->j_task) {
232 wake_up(&journal->j_wait_commit);
233 spin_unlock(&journal->j_state_lock);
234 wait_event(journal->j_wait_done_commit, journal->j_task == 0);
235 spin_lock(&journal->j_state_lock);
237 spin_unlock(&journal->j_state_lock);
241 * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
243 * Writes a metadata buffer to a given disk block. The actual IO is not
244 * performed but a new buffer_head is constructed which labels the data
245 * to be written with the correct destination disk block.
247 * Any magic-number escaping which needs to be done will cause a
248 * copy-out here. If the buffer happens to start with the
249 * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
250 * magic number is only written to the log for descripter blocks. In
251 * this case, we copy the data and replace the first word with 0, and we
252 * return a result code which indicates that this buffer needs to be
253 * marked as an escaped buffer in the corresponding log descriptor
254 * block. The missing word can then be restored when the block is read
255 * during recovery.
257 * If the source buffer has already been modified by a new transaction
258 * since we took the last commit snapshot, we use the frozen copy of
259 * that data for IO. If we end up using the existing buffer_head's data
260 * for the write, then we *have* to lock the buffer to prevent anyone
261 * else from using and possibly modifying it while the IO is in
262 * progress.
264 * The function returns a pointer to the buffer_heads to be used for IO.
266 * We assume that the journal has already been locked in this function.
268 * Return value:
269 * <0: Error
270 * >=0: Finished OK
272 * On success:
273 * Bit 0 set == escape performed on the data
274 * Bit 1 set == buffer copy-out performed (kfree the data after IO)
277 int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
278 struct journal_head *jh_in,
279 struct journal_head **jh_out,
280 unsigned long long blocknr)
282 int need_copy_out = 0;
283 int done_copy_out = 0;
284 int do_escape = 0;
285 char *mapped_data;
286 struct buffer_head *new_bh;
287 struct journal_head *new_jh;
288 struct page *new_page;
289 unsigned int new_offset;
290 struct buffer_head *bh_in = jh2bh(jh_in);
293 * The buffer really shouldn't be locked: only the current committing
294 * transaction is allowed to write it, so nobody else is allowed
295 * to do any IO.
297 * akpm: except if we're journalling data, and write() output is
298 * also part of a shared mapping, and another thread has
299 * decided to launch a writepage() against this buffer.
301 J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
303 new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
306 * If a new transaction has already done a buffer copy-out, then
307 * we use that version of the data for the commit.
309 jbd_lock_bh_state(bh_in);
310 repeat:
311 if (jh_in->b_frozen_data) {
312 done_copy_out = 1;
313 new_page = virt_to_page(jh_in->b_frozen_data);
314 new_offset = offset_in_page(jh_in->b_frozen_data);
315 } else {
316 new_page = jh2bh(jh_in)->b_page;
317 new_offset = offset_in_page(jh2bh(jh_in)->b_data);
320 mapped_data = kmap_atomic(new_page, KM_USER0);
322 * Check for escaping
324 if (*((__be32 *)(mapped_data + new_offset)) ==
325 cpu_to_be32(JBD2_MAGIC_NUMBER)) {
326 need_copy_out = 1;
327 do_escape = 1;
329 kunmap_atomic(mapped_data, KM_USER0);
332 * Do we need to do a data copy?
334 if (need_copy_out && !done_copy_out) {
335 char *tmp;
337 jbd_unlock_bh_state(bh_in);
338 tmp = jbd2_slab_alloc(bh_in->b_size, GFP_NOFS);
339 jbd_lock_bh_state(bh_in);
340 if (jh_in->b_frozen_data) {
341 jbd2_slab_free(tmp, bh_in->b_size);
342 goto repeat;
345 jh_in->b_frozen_data = tmp;
346 mapped_data = kmap_atomic(new_page, KM_USER0);
347 memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size);
348 kunmap_atomic(mapped_data, KM_USER0);
350 new_page = virt_to_page(tmp);
351 new_offset = offset_in_page(tmp);
352 done_copy_out = 1;
356 * Did we need to do an escaping? Now we've done all the
357 * copying, we can finally do so.
359 if (do_escape) {
360 mapped_data = kmap_atomic(new_page, KM_USER0);
361 *((unsigned int *)(mapped_data + new_offset)) = 0;
362 kunmap_atomic(mapped_data, KM_USER0);
365 /* keep subsequent assertions sane */
366 new_bh->b_state = 0;
367 init_buffer(new_bh, NULL, NULL);
368 atomic_set(&new_bh->b_count, 1);
369 jbd_unlock_bh_state(bh_in);
371 new_jh = jbd2_journal_add_journal_head(new_bh); /* This sleeps */
373 set_bh_page(new_bh, new_page, new_offset);
374 new_jh->b_transaction = NULL;
375 new_bh->b_size = jh2bh(jh_in)->b_size;
376 new_bh->b_bdev = transaction->t_journal->j_dev;
377 new_bh->b_blocknr = blocknr;
378 set_buffer_mapped(new_bh);
379 set_buffer_dirty(new_bh);
381 *jh_out = new_jh;
384 * The to-be-written buffer needs to get moved to the io queue,
385 * and the original buffer whose contents we are shadowing or
386 * copying is moved to the transaction's shadow queue.
388 JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
389 jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
390 JBUFFER_TRACE(new_jh, "file as BJ_IO");
391 jbd2_journal_file_buffer(new_jh, transaction, BJ_IO);
393 return do_escape | (done_copy_out << 1);
397 * Allocation code for the journal file. Manage the space left in the
398 * journal, so that we can begin checkpointing when appropriate.
402 * __jbd2_log_space_left: Return the number of free blocks left in the journal.
404 * Called with the journal already locked.
406 * Called under j_state_lock
409 int __jbd2_log_space_left(journal_t *journal)
411 int left = journal->j_free;
413 assert_spin_locked(&journal->j_state_lock);
416 * Be pessimistic here about the number of those free blocks which
417 * might be required for log descriptor control blocks.
420 #define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */
422 left -= MIN_LOG_RESERVED_BLOCKS;
424 if (left <= 0)
425 return 0;
426 left -= (left >> 3);
427 return left;
431 * Called under j_state_lock. Returns true if a transaction was started.
433 int __jbd2_log_start_commit(journal_t *journal, tid_t target)
436 * Are we already doing a recent enough commit?
438 if (!tid_geq(journal->j_commit_request, target)) {
440 * We want a new commit: OK, mark the request and wakup the
441 * commit thread. We do _not_ do the commit ourselves.
444 journal->j_commit_request = target;
445 jbd_debug(1, "JBD: requesting commit %d/%d\n",
446 journal->j_commit_request,
447 journal->j_commit_sequence);
448 wake_up(&journal->j_wait_commit);
449 return 1;
451 return 0;
454 int jbd2_log_start_commit(journal_t *journal, tid_t tid)
456 int ret;
458 spin_lock(&journal->j_state_lock);
459 ret = __jbd2_log_start_commit(journal, tid);
460 spin_unlock(&journal->j_state_lock);
461 return ret;
465 * Force and wait upon a commit if the calling process is not within
466 * transaction. This is used for forcing out undo-protected data which contains
467 * bitmaps, when the fs is running out of space.
469 * We can only force the running transaction if we don't have an active handle;
470 * otherwise, we will deadlock.
472 * Returns true if a transaction was started.
474 int jbd2_journal_force_commit_nested(journal_t *journal)
476 transaction_t *transaction = NULL;
477 tid_t tid;
479 spin_lock(&journal->j_state_lock);
480 if (journal->j_running_transaction && !current->journal_info) {
481 transaction = journal->j_running_transaction;
482 __jbd2_log_start_commit(journal, transaction->t_tid);
483 } else if (journal->j_committing_transaction)
484 transaction = journal->j_committing_transaction;
486 if (!transaction) {
487 spin_unlock(&journal->j_state_lock);
488 return 0; /* Nothing to retry */
491 tid = transaction->t_tid;
492 spin_unlock(&journal->j_state_lock);
493 jbd2_log_wait_commit(journal, tid);
494 return 1;
498 * Start a commit of the current running transaction (if any). Returns true
499 * if a transaction was started, and fills its tid in at *ptid
501 int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
503 int ret = 0;
505 spin_lock(&journal->j_state_lock);
506 if (journal->j_running_transaction) {
507 tid_t tid = journal->j_running_transaction->t_tid;
509 ret = __jbd2_log_start_commit(journal, tid);
510 if (ret && ptid)
511 *ptid = tid;
512 } else if (journal->j_committing_transaction && ptid) {
514 * If ext3_write_super() recently started a commit, then we
515 * have to wait for completion of that transaction
517 *ptid = journal->j_committing_transaction->t_tid;
518 ret = 1;
520 spin_unlock(&journal->j_state_lock);
521 return ret;
525 * Wait for a specified commit to complete.
526 * The caller may not hold the journal lock.
528 int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
530 int err = 0;
532 #ifdef CONFIG_JBD2_DEBUG
533 spin_lock(&journal->j_state_lock);
534 if (!tid_geq(journal->j_commit_request, tid)) {
535 printk(KERN_EMERG
536 "%s: error: j_commit_request=%d, tid=%d\n",
537 __FUNCTION__, journal->j_commit_request, tid);
539 spin_unlock(&journal->j_state_lock);
540 #endif
541 spin_lock(&journal->j_state_lock);
542 while (tid_gt(tid, journal->j_commit_sequence)) {
543 jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n",
544 tid, journal->j_commit_sequence);
545 wake_up(&journal->j_wait_commit);
546 spin_unlock(&journal->j_state_lock);
547 wait_event(journal->j_wait_done_commit,
548 !tid_gt(tid, journal->j_commit_sequence));
549 spin_lock(&journal->j_state_lock);
551 spin_unlock(&journal->j_state_lock);
553 if (unlikely(is_journal_aborted(journal))) {
554 printk(KERN_EMERG "journal commit I/O error\n");
555 err = -EIO;
557 return err;
561 * Log buffer allocation routines:
564 int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
566 unsigned long blocknr;
568 spin_lock(&journal->j_state_lock);
569 J_ASSERT(journal->j_free > 1);
571 blocknr = journal->j_head;
572 journal->j_head++;
573 journal->j_free--;
574 if (journal->j_head == journal->j_last)
575 journal->j_head = journal->j_first;
576 spin_unlock(&journal->j_state_lock);
577 return jbd2_journal_bmap(journal, blocknr, retp);
581 * Conversion of logical to physical block numbers for the journal
583 * On external journals the journal blocks are identity-mapped, so
584 * this is a no-op. If needed, we can use j_blk_offset - everything is
585 * ready.
587 int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
588 unsigned long long *retp)
590 int err = 0;
591 unsigned long long ret;
593 if (journal->j_inode) {
594 ret = bmap(journal->j_inode, blocknr);
595 if (ret)
596 *retp = ret;
597 else {
598 char b[BDEVNAME_SIZE];
600 printk(KERN_ALERT "%s: journal block not found "
601 "at offset %lu on %s\n",
602 __FUNCTION__,
603 blocknr,
604 bdevname(journal->j_dev, b));
605 err = -EIO;
606 __journal_abort_soft(journal, err);
608 } else {
609 *retp = blocknr; /* +journal->j_blk_offset */
611 return err;
615 * We play buffer_head aliasing tricks to write data/metadata blocks to
616 * the journal without copying their contents, but for journal
617 * descriptor blocks we do need to generate bona fide buffers.
619 * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
620 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
621 * But we don't bother doing that, so there will be coherency problems with
622 * mmaps of blockdevs which hold live JBD-controlled filesystems.
624 struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
626 struct buffer_head *bh;
627 unsigned long long blocknr;
628 int err;
630 err = jbd2_journal_next_log_block(journal, &blocknr);
632 if (err)
633 return NULL;
635 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
636 lock_buffer(bh);
637 memset(bh->b_data, 0, journal->j_blocksize);
638 set_buffer_uptodate(bh);
639 unlock_buffer(bh);
640 BUFFER_TRACE(bh, "return this buffer");
641 return jbd2_journal_add_journal_head(bh);
645 * Management for journal control blocks: functions to create and
646 * destroy journal_t structures, and to initialise and read existing
647 * journal blocks from disk. */
649 /* First: create and setup a journal_t object in memory. We initialise
650 * very few fields yet: that has to wait until we have created the
651 * journal structures from from scratch, or loaded them from disk. */
653 static journal_t * journal_init_common (void)
655 journal_t *journal;
656 int err;
658 journal = jbd_kmalloc(sizeof(*journal), GFP_KERNEL);
659 if (!journal)
660 goto fail;
661 memset(journal, 0, sizeof(*journal));
663 init_waitqueue_head(&journal->j_wait_transaction_locked);
664 init_waitqueue_head(&journal->j_wait_logspace);
665 init_waitqueue_head(&journal->j_wait_done_commit);
666 init_waitqueue_head(&journal->j_wait_checkpoint);
667 init_waitqueue_head(&journal->j_wait_commit);
668 init_waitqueue_head(&journal->j_wait_updates);
669 mutex_init(&journal->j_barrier);
670 mutex_init(&journal->j_checkpoint_mutex);
671 spin_lock_init(&journal->j_revoke_lock);
672 spin_lock_init(&journal->j_list_lock);
673 spin_lock_init(&journal->j_state_lock);
675 journal->j_commit_interval = (HZ * JBD_DEFAULT_MAX_COMMIT_AGE);
677 /* The journal is marked for error until we succeed with recovery! */
678 journal->j_flags = JBD2_ABORT;
680 /* Set up a default-sized revoke table for the new mount. */
681 err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
682 if (err) {
683 kfree(journal);
684 goto fail;
686 return journal;
687 fail:
688 return NULL;
691 /* jbd2_journal_init_dev and jbd2_journal_init_inode:
693 * Create a journal structure assigned some fixed set of disk blocks to
694 * the journal. We don't actually touch those disk blocks yet, but we
695 * need to set up all of the mapping information to tell the journaling
696 * system where the journal blocks are.
701 * journal_t * jbd2_journal_init_dev() - creates an initialises a journal structure
702 * @bdev: Block device on which to create the journal
703 * @fs_dev: Device which hold journalled filesystem for this journal.
704 * @start: Block nr Start of journal.
705 * @len: Length of the journal in blocks.
706 * @blocksize: blocksize of journalling device
707 * @returns: a newly created journal_t *
709 * jbd2_journal_init_dev creates a journal which maps a fixed contiguous
710 * range of blocks on an arbitrary block device.
713 journal_t * jbd2_journal_init_dev(struct block_device *bdev,
714 struct block_device *fs_dev,
715 unsigned long long start, int len, int blocksize)
717 journal_t *journal = journal_init_common();
718 struct buffer_head *bh;
719 int n;
721 if (!journal)
722 return NULL;
724 /* journal descriptor can store up to n blocks -bzzz */
725 journal->j_blocksize = blocksize;
726 n = journal->j_blocksize / sizeof(journal_block_tag_t);
727 journal->j_wbufsize = n;
728 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
729 if (!journal->j_wbuf) {
730 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
731 __FUNCTION__);
732 kfree(journal);
733 journal = NULL;
734 goto out;
736 journal->j_dev = bdev;
737 journal->j_fs_dev = fs_dev;
738 journal->j_blk_offset = start;
739 journal->j_maxlen = len;
741 bh = __getblk(journal->j_dev, start, journal->j_blocksize);
742 J_ASSERT(bh != NULL);
743 journal->j_sb_buffer = bh;
744 journal->j_superblock = (journal_superblock_t *)bh->b_data;
745 out:
746 return journal;
750 * journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
751 * @inode: An inode to create the journal in
753 * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
754 * the journal. The inode must exist already, must support bmap() and
755 * must have all data blocks preallocated.
757 journal_t * jbd2_journal_init_inode (struct inode *inode)
759 struct buffer_head *bh;
760 journal_t *journal = journal_init_common();
761 int err;
762 int n;
763 unsigned long long blocknr;
765 if (!journal)
766 return NULL;
768 journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
769 journal->j_inode = inode;
770 jbd_debug(1,
771 "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
772 journal, inode->i_sb->s_id, inode->i_ino,
773 (long long) inode->i_size,
774 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
776 journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
777 journal->j_blocksize = inode->i_sb->s_blocksize;
779 /* journal descriptor can store up to n blocks -bzzz */
780 n = journal->j_blocksize / sizeof(journal_block_tag_t);
781 journal->j_wbufsize = n;
782 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
783 if (!journal->j_wbuf) {
784 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
785 __FUNCTION__);
786 kfree(journal);
787 return NULL;
790 err = jbd2_journal_bmap(journal, 0, &blocknr);
791 /* If that failed, give up */
792 if (err) {
793 printk(KERN_ERR "%s: Cannnot locate journal superblock\n",
794 __FUNCTION__);
795 kfree(journal);
796 return NULL;
799 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
800 J_ASSERT(bh != NULL);
801 journal->j_sb_buffer = bh;
802 journal->j_superblock = (journal_superblock_t *)bh->b_data;
804 return journal;
808 * If the journal init or create aborts, we need to mark the journal
809 * superblock as being NULL to prevent the journal destroy from writing
810 * back a bogus superblock.
812 static void journal_fail_superblock (journal_t *journal)
814 struct buffer_head *bh = journal->j_sb_buffer;
815 brelse(bh);
816 journal->j_sb_buffer = NULL;
820 * Given a journal_t structure, initialise the various fields for
821 * startup of a new journaling session. We use this both when creating
822 * a journal, and after recovering an old journal to reset it for
823 * subsequent use.
826 static int journal_reset(journal_t *journal)
828 journal_superblock_t *sb = journal->j_superblock;
829 unsigned long long first, last;
831 first = be32_to_cpu(sb->s_first);
832 last = be32_to_cpu(sb->s_maxlen);
834 journal->j_first = first;
835 journal->j_last = last;
837 journal->j_head = first;
838 journal->j_tail = first;
839 journal->j_free = last - first;
841 journal->j_tail_sequence = journal->j_transaction_sequence;
842 journal->j_commit_sequence = journal->j_transaction_sequence - 1;
843 journal->j_commit_request = journal->j_commit_sequence;
845 journal->j_max_transaction_buffers = journal->j_maxlen / 4;
847 /* Add the dynamic fields and write it to disk. */
848 jbd2_journal_update_superblock(journal, 1);
849 return jbd2_journal_start_thread(journal);
853 * int jbd2_journal_create() - Initialise the new journal file
854 * @journal: Journal to create. This structure must have been initialised
856 * Given a journal_t structure which tells us which disk blocks we can
857 * use, create a new journal superblock and initialise all of the
858 * journal fields from scratch.
860 int jbd2_journal_create(journal_t *journal)
862 unsigned long long blocknr;
863 struct buffer_head *bh;
864 journal_superblock_t *sb;
865 int i, err;
867 if (journal->j_maxlen < JBD2_MIN_JOURNAL_BLOCKS) {
868 printk (KERN_ERR "Journal length (%d blocks) too short.\n",
869 journal->j_maxlen);
870 journal_fail_superblock(journal);
871 return -EINVAL;
874 if (journal->j_inode == NULL) {
876 * We don't know what block to start at!
878 printk(KERN_EMERG
879 "%s: creation of journal on external device!\n",
880 __FUNCTION__);
881 BUG();
884 /* Zero out the entire journal on disk. We cannot afford to
885 have any blocks on disk beginning with JBD2_MAGIC_NUMBER. */
886 jbd_debug(1, "JBD: Zeroing out journal blocks...\n");
887 for (i = 0; i < journal->j_maxlen; i++) {
888 err = jbd2_journal_bmap(journal, i, &blocknr);
889 if (err)
890 return err;
891 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
892 lock_buffer(bh);
893 memset (bh->b_data, 0, journal->j_blocksize);
894 BUFFER_TRACE(bh, "marking dirty");
895 mark_buffer_dirty(bh);
896 BUFFER_TRACE(bh, "marking uptodate");
897 set_buffer_uptodate(bh);
898 unlock_buffer(bh);
899 __brelse(bh);
902 sync_blockdev(journal->j_dev);
903 jbd_debug(1, "JBD: journal cleared.\n");
905 /* OK, fill in the initial static fields in the new superblock */
906 sb = journal->j_superblock;
908 sb->s_header.h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
909 sb->s_header.h_blocktype = cpu_to_be32(JBD2_SUPERBLOCK_V2);
911 sb->s_blocksize = cpu_to_be32(journal->j_blocksize);
912 sb->s_maxlen = cpu_to_be32(journal->j_maxlen);
913 sb->s_first = cpu_to_be32(1);
915 journal->j_transaction_sequence = 1;
917 journal->j_flags &= ~JBD2_ABORT;
918 journal->j_format_version = 2;
920 return journal_reset(journal);
924 * void jbd2_journal_update_superblock() - Update journal sb on disk.
925 * @journal: The journal to update.
926 * @wait: Set to '0' if you don't want to wait for IO completion.
928 * Update a journal's dynamic superblock fields and write it to disk,
929 * optionally waiting for the IO to complete.
931 void jbd2_journal_update_superblock(journal_t *journal, int wait)
933 journal_superblock_t *sb = journal->j_superblock;
934 struct buffer_head *bh = journal->j_sb_buffer;
937 * As a special case, if the on-disk copy is already marked as needing
938 * no recovery (s_start == 0) and there are no outstanding transactions
939 * in the filesystem, then we can safely defer the superblock update
940 * until the next commit by setting JBD2_FLUSHED. This avoids
941 * attempting a write to a potential-readonly device.
943 if (sb->s_start == 0 && journal->j_tail_sequence ==
944 journal->j_transaction_sequence) {
945 jbd_debug(1,"JBD: Skipping superblock update on recovered sb "
946 "(start %ld, seq %d, errno %d)\n",
947 journal->j_tail, journal->j_tail_sequence,
948 journal->j_errno);
949 goto out;
952 spin_lock(&journal->j_state_lock);
953 jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n",
954 journal->j_tail, journal->j_tail_sequence, journal->j_errno);
956 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
957 sb->s_start = cpu_to_be32(journal->j_tail);
958 sb->s_errno = cpu_to_be32(journal->j_errno);
959 spin_unlock(&journal->j_state_lock);
961 BUFFER_TRACE(bh, "marking dirty");
962 mark_buffer_dirty(bh);
963 if (wait)
964 sync_dirty_buffer(bh);
965 else
966 ll_rw_block(SWRITE, 1, &bh);
968 out:
969 /* If we have just flushed the log (by marking s_start==0), then
970 * any future commit will have to be careful to update the
971 * superblock again to re-record the true start of the log. */
973 spin_lock(&journal->j_state_lock);
974 if (sb->s_start)
975 journal->j_flags &= ~JBD2_FLUSHED;
976 else
977 journal->j_flags |= JBD2_FLUSHED;
978 spin_unlock(&journal->j_state_lock);
982 * Read the superblock for a given journal, performing initial
983 * validation of the format.
986 static int journal_get_superblock(journal_t *journal)
988 struct buffer_head *bh;
989 journal_superblock_t *sb;
990 int err = -EIO;
992 bh = journal->j_sb_buffer;
994 J_ASSERT(bh != NULL);
995 if (!buffer_uptodate(bh)) {
996 ll_rw_block(READ, 1, &bh);
997 wait_on_buffer(bh);
998 if (!buffer_uptodate(bh)) {
999 printk (KERN_ERR
1000 "JBD: IO error reading journal superblock\n");
1001 goto out;
1005 sb = journal->j_superblock;
1007 err = -EINVAL;
1009 if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1010 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1011 printk(KERN_WARNING "JBD: no valid journal superblock found\n");
1012 goto out;
1015 switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1016 case JBD2_SUPERBLOCK_V1:
1017 journal->j_format_version = 1;
1018 break;
1019 case JBD2_SUPERBLOCK_V2:
1020 journal->j_format_version = 2;
1021 break;
1022 default:
1023 printk(KERN_WARNING "JBD: unrecognised superblock format ID\n");
1024 goto out;
1027 if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
1028 journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
1029 else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
1030 printk (KERN_WARNING "JBD: journal file too short\n");
1031 goto out;
1034 return 0;
1036 out:
1037 journal_fail_superblock(journal);
1038 return err;
1042 * Load the on-disk journal superblock and read the key fields into the
1043 * journal_t.
1046 static int load_superblock(journal_t *journal)
1048 int err;
1049 journal_superblock_t *sb;
1051 err = journal_get_superblock(journal);
1052 if (err)
1053 return err;
1055 sb = journal->j_superblock;
1057 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1058 journal->j_tail = be32_to_cpu(sb->s_start);
1059 journal->j_first = be32_to_cpu(sb->s_first);
1060 journal->j_last = be32_to_cpu(sb->s_maxlen);
1061 journal->j_errno = be32_to_cpu(sb->s_errno);
1063 return 0;
1068 * int jbd2_journal_load() - Read journal from disk.
1069 * @journal: Journal to act on.
1071 * Given a journal_t structure which tells us which disk blocks contain
1072 * a journal, read the journal from disk to initialise the in-memory
1073 * structures.
1075 int jbd2_journal_load(journal_t *journal)
1077 int err;
1078 journal_superblock_t *sb;
1080 err = load_superblock(journal);
1081 if (err)
1082 return err;
1084 sb = journal->j_superblock;
1085 /* If this is a V2 superblock, then we have to check the
1086 * features flags on it. */
1088 if (journal->j_format_version >= 2) {
1089 if ((sb->s_feature_ro_compat &
1090 ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
1091 (sb->s_feature_incompat &
1092 ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
1093 printk (KERN_WARNING
1094 "JBD: Unrecognised features on journal\n");
1095 return -EINVAL;
1100 * Create a slab for this blocksize
1102 err = jbd2_journal_create_jbd_slab(be32_to_cpu(sb->s_blocksize));
1103 if (err)
1104 return err;
1106 /* Let the recovery code check whether it needs to recover any
1107 * data from the journal. */
1108 if (jbd2_journal_recover(journal))
1109 goto recovery_error;
1111 /* OK, we've finished with the dynamic journal bits:
1112 * reinitialise the dynamic contents of the superblock in memory
1113 * and reset them on disk. */
1114 if (journal_reset(journal))
1115 goto recovery_error;
1117 journal->j_flags &= ~JBD2_ABORT;
1118 journal->j_flags |= JBD2_LOADED;
1119 return 0;
1121 recovery_error:
1122 printk (KERN_WARNING "JBD: recovery failed\n");
1123 return -EIO;
1127 * void jbd2_journal_destroy() - Release a journal_t structure.
1128 * @journal: Journal to act on.
1130 * Release a journal_t structure once it is no longer in use by the
1131 * journaled object.
1133 void jbd2_journal_destroy(journal_t *journal)
1135 /* Wait for the commit thread to wake up and die. */
1136 journal_kill_thread(journal);
1138 /* Force a final log commit */
1139 if (journal->j_running_transaction)
1140 jbd2_journal_commit_transaction(journal);
1142 /* Force any old transactions to disk */
1144 /* Totally anal locking here... */
1145 spin_lock(&journal->j_list_lock);
1146 while (journal->j_checkpoint_transactions != NULL) {
1147 spin_unlock(&journal->j_list_lock);
1148 jbd2_log_do_checkpoint(journal);
1149 spin_lock(&journal->j_list_lock);
1152 J_ASSERT(journal->j_running_transaction == NULL);
1153 J_ASSERT(journal->j_committing_transaction == NULL);
1154 J_ASSERT(journal->j_checkpoint_transactions == NULL);
1155 spin_unlock(&journal->j_list_lock);
1157 /* We can now mark the journal as empty. */
1158 journal->j_tail = 0;
1159 journal->j_tail_sequence = ++journal->j_transaction_sequence;
1160 if (journal->j_sb_buffer) {
1161 jbd2_journal_update_superblock(journal, 1);
1162 brelse(journal->j_sb_buffer);
1165 if (journal->j_inode)
1166 iput(journal->j_inode);
1167 if (journal->j_revoke)
1168 jbd2_journal_destroy_revoke(journal);
1169 kfree(journal->j_wbuf);
1170 kfree(journal);
1175 *int jbd2_journal_check_used_features () - Check if features specified are used.
1176 * @journal: Journal to check.
1177 * @compat: bitmask of compatible features
1178 * @ro: bitmask of features that force read-only mount
1179 * @incompat: bitmask of incompatible features
1181 * Check whether the journal uses all of a given set of
1182 * features. Return true (non-zero) if it does.
1185 int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,
1186 unsigned long ro, unsigned long incompat)
1188 journal_superblock_t *sb;
1190 if (!compat && !ro && !incompat)
1191 return 1;
1192 if (journal->j_format_version == 1)
1193 return 0;
1195 sb = journal->j_superblock;
1197 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
1198 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
1199 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
1200 return 1;
1202 return 0;
1206 * int jbd2_journal_check_available_features() - Check feature set in journalling layer
1207 * @journal: Journal to check.
1208 * @compat: bitmask of compatible features
1209 * @ro: bitmask of features that force read-only mount
1210 * @incompat: bitmask of incompatible features
1212 * Check whether the journaling code supports the use of
1213 * all of a given set of features on this journal. Return true
1214 * (non-zero) if it can. */
1216 int jbd2_journal_check_available_features (journal_t *journal, unsigned long compat,
1217 unsigned long ro, unsigned long incompat)
1219 journal_superblock_t *sb;
1221 if (!compat && !ro && !incompat)
1222 return 1;
1224 sb = journal->j_superblock;
1226 /* We can support any known requested features iff the
1227 * superblock is in version 2. Otherwise we fail to support any
1228 * extended sb features. */
1230 if (journal->j_format_version != 2)
1231 return 0;
1233 if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
1234 (ro & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
1235 (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
1236 return 1;
1238 return 0;
1242 * int jbd2_journal_set_features () - Mark a given journal feature in the superblock
1243 * @journal: Journal to act on.
1244 * @compat: bitmask of compatible features
1245 * @ro: bitmask of features that force read-only mount
1246 * @incompat: bitmask of incompatible features
1248 * Mark a given journal feature as present on the
1249 * superblock. Returns true if the requested features could be set.
1253 int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
1254 unsigned long ro, unsigned long incompat)
1256 journal_superblock_t *sb;
1258 if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
1259 return 1;
1261 if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
1262 return 0;
1264 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1265 compat, ro, incompat);
1267 sb = journal->j_superblock;
1269 sb->s_feature_compat |= cpu_to_be32(compat);
1270 sb->s_feature_ro_compat |= cpu_to_be32(ro);
1271 sb->s_feature_incompat |= cpu_to_be32(incompat);
1273 return 1;
1278 * int jbd2_journal_update_format () - Update on-disk journal structure.
1279 * @journal: Journal to act on.
1281 * Given an initialised but unloaded journal struct, poke about in the
1282 * on-disk structure to update it to the most recent supported version.
1284 int jbd2_journal_update_format (journal_t *journal)
1286 journal_superblock_t *sb;
1287 int err;
1289 err = journal_get_superblock(journal);
1290 if (err)
1291 return err;
1293 sb = journal->j_superblock;
1295 switch (be32_to_cpu(sb->s_header.h_blocktype)) {
1296 case JBD2_SUPERBLOCK_V2:
1297 return 0;
1298 case JBD2_SUPERBLOCK_V1:
1299 return journal_convert_superblock_v1(journal, sb);
1300 default:
1301 break;
1303 return -EINVAL;
1306 static int journal_convert_superblock_v1(journal_t *journal,
1307 journal_superblock_t *sb)
1309 int offset, blocksize;
1310 struct buffer_head *bh;
1312 printk(KERN_WARNING
1313 "JBD: Converting superblock from version 1 to 2.\n");
1315 /* Pre-initialise new fields to zero */
1316 offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
1317 blocksize = be32_to_cpu(sb->s_blocksize);
1318 memset(&sb->s_feature_compat, 0, blocksize-offset);
1320 sb->s_nr_users = cpu_to_be32(1);
1321 sb->s_header.h_blocktype = cpu_to_be32(JBD2_SUPERBLOCK_V2);
1322 journal->j_format_version = 2;
1324 bh = journal->j_sb_buffer;
1325 BUFFER_TRACE(bh, "marking dirty");
1326 mark_buffer_dirty(bh);
1327 sync_dirty_buffer(bh);
1328 return 0;
1333 * int jbd2_journal_flush () - Flush journal
1334 * @journal: Journal to act on.
1336 * Flush all data for a given journal to disk and empty the journal.
1337 * Filesystems can use this when remounting readonly to ensure that
1338 * recovery does not need to happen on remount.
1341 int jbd2_journal_flush(journal_t *journal)
1343 int err = 0;
1344 transaction_t *transaction = NULL;
1345 unsigned long old_tail;
1347 spin_lock(&journal->j_state_lock);
1349 /* Force everything buffered to the log... */
1350 if (journal->j_running_transaction) {
1351 transaction = journal->j_running_transaction;
1352 __jbd2_log_start_commit(journal, transaction->t_tid);
1353 } else if (journal->j_committing_transaction)
1354 transaction = journal->j_committing_transaction;
1356 /* Wait for the log commit to complete... */
1357 if (transaction) {
1358 tid_t tid = transaction->t_tid;
1360 spin_unlock(&journal->j_state_lock);
1361 jbd2_log_wait_commit(journal, tid);
1362 } else {
1363 spin_unlock(&journal->j_state_lock);
1366 /* ...and flush everything in the log out to disk. */
1367 spin_lock(&journal->j_list_lock);
1368 while (!err && journal->j_checkpoint_transactions != NULL) {
1369 spin_unlock(&journal->j_list_lock);
1370 err = jbd2_log_do_checkpoint(journal);
1371 spin_lock(&journal->j_list_lock);
1373 spin_unlock(&journal->j_list_lock);
1374 jbd2_cleanup_journal_tail(journal);
1376 /* Finally, mark the journal as really needing no recovery.
1377 * This sets s_start==0 in the underlying superblock, which is
1378 * the magic code for a fully-recovered superblock. Any future
1379 * commits of data to the journal will restore the current
1380 * s_start value. */
1381 spin_lock(&journal->j_state_lock);
1382 old_tail = journal->j_tail;
1383 journal->j_tail = 0;
1384 spin_unlock(&journal->j_state_lock);
1385 jbd2_journal_update_superblock(journal, 1);
1386 spin_lock(&journal->j_state_lock);
1387 journal->j_tail = old_tail;
1389 J_ASSERT(!journal->j_running_transaction);
1390 J_ASSERT(!journal->j_committing_transaction);
1391 J_ASSERT(!journal->j_checkpoint_transactions);
1392 J_ASSERT(journal->j_head == journal->j_tail);
1393 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
1394 spin_unlock(&journal->j_state_lock);
1395 return err;
1399 * int jbd2_journal_wipe() - Wipe journal contents
1400 * @journal: Journal to act on.
1401 * @write: flag (see below)
1403 * Wipe out all of the contents of a journal, safely. This will produce
1404 * a warning if the journal contains any valid recovery information.
1405 * Must be called between journal_init_*() and jbd2_journal_load().
1407 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
1408 * we merely suppress recovery.
1411 int jbd2_journal_wipe(journal_t *journal, int write)
1413 journal_superblock_t *sb;
1414 int err = 0;
1416 J_ASSERT (!(journal->j_flags & JBD2_LOADED));
1418 err = load_superblock(journal);
1419 if (err)
1420 return err;
1422 sb = journal->j_superblock;
1424 if (!journal->j_tail)
1425 goto no_recovery;
1427 printk (KERN_WARNING "JBD: %s recovery information on journal\n",
1428 write ? "Clearing" : "Ignoring");
1430 err = jbd2_journal_skip_recovery(journal);
1431 if (write)
1432 jbd2_journal_update_superblock(journal, 1);
1434 no_recovery:
1435 return err;
1439 * journal_dev_name: format a character string to describe on what
1440 * device this journal is present.
1443 static const char *journal_dev_name(journal_t *journal, char *buffer)
1445 struct block_device *bdev;
1447 if (journal->j_inode)
1448 bdev = journal->j_inode->i_sb->s_bdev;
1449 else
1450 bdev = journal->j_dev;
1452 return bdevname(bdev, buffer);
1456 * Journal abort has very specific semantics, which we describe
1457 * for journal abort.
1459 * Two internal function, which provide abort to te jbd layer
1460 * itself are here.
1464 * Quick version for internal journal use (doesn't lock the journal).
1465 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
1466 * and don't attempt to make any other journal updates.
1468 void __jbd2_journal_abort_hard(journal_t *journal)
1470 transaction_t *transaction;
1471 char b[BDEVNAME_SIZE];
1473 if (journal->j_flags & JBD2_ABORT)
1474 return;
1476 printk(KERN_ERR "Aborting journal on device %s.\n",
1477 journal_dev_name(journal, b));
1479 spin_lock(&journal->j_state_lock);
1480 journal->j_flags |= JBD2_ABORT;
1481 transaction = journal->j_running_transaction;
1482 if (transaction)
1483 __jbd2_log_start_commit(journal, transaction->t_tid);
1484 spin_unlock(&journal->j_state_lock);
1487 /* Soft abort: record the abort error status in the journal superblock,
1488 * but don't do any other IO. */
1489 static void __journal_abort_soft (journal_t *journal, int errno)
1491 if (journal->j_flags & JBD2_ABORT)
1492 return;
1494 if (!journal->j_errno)
1495 journal->j_errno = errno;
1497 __jbd2_journal_abort_hard(journal);
1499 if (errno)
1500 jbd2_journal_update_superblock(journal, 1);
1504 * void jbd2_journal_abort () - Shutdown the journal immediately.
1505 * @journal: the journal to shutdown.
1506 * @errno: an error number to record in the journal indicating
1507 * the reason for the shutdown.
1509 * Perform a complete, immediate shutdown of the ENTIRE
1510 * journal (not of a single transaction). This operation cannot be
1511 * undone without closing and reopening the journal.
1513 * The jbd2_journal_abort function is intended to support higher level error
1514 * recovery mechanisms such as the ext2/ext3 remount-readonly error
1515 * mode.
1517 * Journal abort has very specific semantics. Any existing dirty,
1518 * unjournaled buffers in the main filesystem will still be written to
1519 * disk by bdflush, but the journaling mechanism will be suspended
1520 * immediately and no further transaction commits will be honoured.
1522 * Any dirty, journaled buffers will be written back to disk without
1523 * hitting the journal. Atomicity cannot be guaranteed on an aborted
1524 * filesystem, but we _do_ attempt to leave as much data as possible
1525 * behind for fsck to use for cleanup.
1527 * Any attempt to get a new transaction handle on a journal which is in
1528 * ABORT state will just result in an -EROFS error return. A
1529 * jbd2_journal_stop on an existing handle will return -EIO if we have
1530 * entered abort state during the update.
1532 * Recursive transactions are not disturbed by journal abort until the
1533 * final jbd2_journal_stop, which will receive the -EIO error.
1535 * Finally, the jbd2_journal_abort call allows the caller to supply an errno
1536 * which will be recorded (if possible) in the journal superblock. This
1537 * allows a client to record failure conditions in the middle of a
1538 * transaction without having to complete the transaction to record the
1539 * failure to disk. ext3_error, for example, now uses this
1540 * functionality.
1542 * Errors which originate from within the journaling layer will NOT
1543 * supply an errno; a null errno implies that absolutely no further
1544 * writes are done to the journal (unless there are any already in
1545 * progress).
1549 void jbd2_journal_abort(journal_t *journal, int errno)
1551 __journal_abort_soft(journal, errno);
1555 * int jbd2_journal_errno () - returns the journal's error state.
1556 * @journal: journal to examine.
1558 * This is the errno numbet set with jbd2_journal_abort(), the last
1559 * time the journal was mounted - if the journal was stopped
1560 * without calling abort this will be 0.
1562 * If the journal has been aborted on this mount time -EROFS will
1563 * be returned.
1565 int jbd2_journal_errno(journal_t *journal)
1567 int err;
1569 spin_lock(&journal->j_state_lock);
1570 if (journal->j_flags & JBD2_ABORT)
1571 err = -EROFS;
1572 else
1573 err = journal->j_errno;
1574 spin_unlock(&journal->j_state_lock);
1575 return err;
1579 * int jbd2_journal_clear_err () - clears the journal's error state
1580 * @journal: journal to act on.
1582 * An error must be cleared or Acked to take a FS out of readonly
1583 * mode.
1585 int jbd2_journal_clear_err(journal_t *journal)
1587 int err = 0;
1589 spin_lock(&journal->j_state_lock);
1590 if (journal->j_flags & JBD2_ABORT)
1591 err = -EROFS;
1592 else
1593 journal->j_errno = 0;
1594 spin_unlock(&journal->j_state_lock);
1595 return err;
1599 * void jbd2_journal_ack_err() - Ack journal err.
1600 * @journal: journal to act on.
1602 * An error must be cleared or Acked to take a FS out of readonly
1603 * mode.
1605 void jbd2_journal_ack_err(journal_t *journal)
1607 spin_lock(&journal->j_state_lock);
1608 if (journal->j_errno)
1609 journal->j_flags |= JBD2_ACK_ERR;
1610 spin_unlock(&journal->j_state_lock);
1613 int jbd2_journal_blocks_per_page(struct inode *inode)
1615 return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
1619 * helper functions to deal with 32 or 64bit block numbers.
1621 size_t journal_tag_bytes(journal_t *journal)
1623 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
1624 return JBD_TAG_SIZE64;
1625 else
1626 return JBD_TAG_SIZE32;
1630 * Simple support for retrying memory allocations. Introduced to help to
1631 * debug different VM deadlock avoidance strategies.
1633 void * __jbd2_kmalloc (const char *where, size_t size, gfp_t flags, int retry)
1635 return kmalloc(size, flags | (retry ? __GFP_NOFAIL : 0));
1639 * jbd slab management: create 1k, 2k, 4k, 8k slabs as needed
1640 * and allocate frozen and commit buffers from these slabs.
1642 * Reason for doing this is to avoid, SLAB_DEBUG - since it could
1643 * cause bh to cross page boundary.
1646 #define JBD_MAX_SLABS 5
1647 #define JBD_SLAB_INDEX(size) (size >> 11)
1649 static struct kmem_cache *jbd_slab[JBD_MAX_SLABS];
1650 static const char *jbd_slab_names[JBD_MAX_SLABS] = {
1651 "jbd2_1k", "jbd2_2k", "jbd2_4k", NULL, "jbd2_8k"
1654 static void jbd2_journal_destroy_jbd_slabs(void)
1656 int i;
1658 for (i = 0; i < JBD_MAX_SLABS; i++) {
1659 if (jbd_slab[i])
1660 kmem_cache_destroy(jbd_slab[i]);
1661 jbd_slab[i] = NULL;
1665 static int jbd2_journal_create_jbd_slab(size_t slab_size)
1667 int i = JBD_SLAB_INDEX(slab_size);
1669 BUG_ON(i >= JBD_MAX_SLABS);
1672 * Check if we already have a slab created for this size
1674 if (jbd_slab[i])
1675 return 0;
1678 * Create a slab and force alignment to be same as slabsize -
1679 * this will make sure that allocations won't cross the page
1680 * boundary.
1682 jbd_slab[i] = kmem_cache_create(jbd_slab_names[i],
1683 slab_size, slab_size, 0, NULL);
1684 if (!jbd_slab[i]) {
1685 printk(KERN_EMERG "JBD: no memory for jbd_slab cache\n");
1686 return -ENOMEM;
1688 return 0;
1691 void * jbd2_slab_alloc(size_t size, gfp_t flags)
1693 int idx;
1695 idx = JBD_SLAB_INDEX(size);
1696 BUG_ON(jbd_slab[idx] == NULL);
1697 return kmem_cache_alloc(jbd_slab[idx], flags | __GFP_NOFAIL);
1700 void jbd2_slab_free(void *ptr, size_t size)
1702 int idx;
1704 idx = JBD_SLAB_INDEX(size);
1705 BUG_ON(jbd_slab[idx] == NULL);
1706 kmem_cache_free(jbd_slab[idx], ptr);
1710 * Journal_head storage management
1712 static struct kmem_cache *jbd2_journal_head_cache;
1713 #ifdef CONFIG_JBD2_DEBUG
1714 static atomic_t nr_journal_heads = ATOMIC_INIT(0);
1715 #endif
1717 static int journal_init_jbd2_journal_head_cache(void)
1719 int retval;
1721 J_ASSERT(jbd2_journal_head_cache == 0);
1722 jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
1723 sizeof(struct journal_head),
1724 0, /* offset */
1725 0, /* flags */
1726 NULL); /* ctor */
1727 retval = 0;
1728 if (jbd2_journal_head_cache == 0) {
1729 retval = -ENOMEM;
1730 printk(KERN_EMERG "JBD: no memory for journal_head cache\n");
1732 return retval;
1735 static void jbd2_journal_destroy_jbd2_journal_head_cache(void)
1737 J_ASSERT(jbd2_journal_head_cache != NULL);
1738 kmem_cache_destroy(jbd2_journal_head_cache);
1739 jbd2_journal_head_cache = NULL;
1743 * journal_head splicing and dicing
1745 static struct journal_head *journal_alloc_journal_head(void)
1747 struct journal_head *ret;
1748 static unsigned long last_warning;
1750 #ifdef CONFIG_JBD2_DEBUG
1751 atomic_inc(&nr_journal_heads);
1752 #endif
1753 ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS);
1754 if (ret == 0) {
1755 jbd_debug(1, "out of memory for journal_head\n");
1756 if (time_after(jiffies, last_warning + 5*HZ)) {
1757 printk(KERN_NOTICE "ENOMEM in %s, retrying.\n",
1758 __FUNCTION__);
1759 last_warning = jiffies;
1761 while (ret == 0) {
1762 yield();
1763 ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS);
1766 return ret;
1769 static void journal_free_journal_head(struct journal_head *jh)
1771 #ifdef CONFIG_JBD2_DEBUG
1772 atomic_dec(&nr_journal_heads);
1773 memset(jh, JBD_POISON_FREE, sizeof(*jh));
1774 #endif
1775 kmem_cache_free(jbd2_journal_head_cache, jh);
1779 * A journal_head is attached to a buffer_head whenever JBD has an
1780 * interest in the buffer.
1782 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
1783 * is set. This bit is tested in core kernel code where we need to take
1784 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
1785 * there.
1787 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
1789 * When a buffer has its BH_JBD bit set it is immune from being released by
1790 * core kernel code, mainly via ->b_count.
1792 * A journal_head may be detached from its buffer_head when the journal_head's
1793 * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL.
1794 * Various places in JBD call jbd2_journal_remove_journal_head() to indicate that the
1795 * journal_head can be dropped if needed.
1797 * Various places in the kernel want to attach a journal_head to a buffer_head
1798 * _before_ attaching the journal_head to a transaction. To protect the
1799 * journal_head in this situation, jbd2_journal_add_journal_head elevates the
1800 * journal_head's b_jcount refcount by one. The caller must call
1801 * jbd2_journal_put_journal_head() to undo this.
1803 * So the typical usage would be:
1805 * (Attach a journal_head if needed. Increments b_jcount)
1806 * struct journal_head *jh = jbd2_journal_add_journal_head(bh);
1807 * ...
1808 * jh->b_transaction = xxx;
1809 * jbd2_journal_put_journal_head(jh);
1811 * Now, the journal_head's b_jcount is zero, but it is safe from being released
1812 * because it has a non-zero b_transaction.
1816 * Give a buffer_head a journal_head.
1818 * Doesn't need the journal lock.
1819 * May sleep.
1821 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
1823 struct journal_head *jh;
1824 struct journal_head *new_jh = NULL;
1826 repeat:
1827 if (!buffer_jbd(bh)) {
1828 new_jh = journal_alloc_journal_head();
1829 memset(new_jh, 0, sizeof(*new_jh));
1832 jbd_lock_bh_journal_head(bh);
1833 if (buffer_jbd(bh)) {
1834 jh = bh2jh(bh);
1835 } else {
1836 J_ASSERT_BH(bh,
1837 (atomic_read(&bh->b_count) > 0) ||
1838 (bh->b_page && bh->b_page->mapping));
1840 if (!new_jh) {
1841 jbd_unlock_bh_journal_head(bh);
1842 goto repeat;
1845 jh = new_jh;
1846 new_jh = NULL; /* We consumed it */
1847 set_buffer_jbd(bh);
1848 bh->b_private = jh;
1849 jh->b_bh = bh;
1850 get_bh(bh);
1851 BUFFER_TRACE(bh, "added journal_head");
1853 jh->b_jcount++;
1854 jbd_unlock_bh_journal_head(bh);
1855 if (new_jh)
1856 journal_free_journal_head(new_jh);
1857 return bh->b_private;
1861 * Grab a ref against this buffer_head's journal_head. If it ended up not
1862 * having a journal_head, return NULL
1864 struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
1866 struct journal_head *jh = NULL;
1868 jbd_lock_bh_journal_head(bh);
1869 if (buffer_jbd(bh)) {
1870 jh = bh2jh(bh);
1871 jh->b_jcount++;
1873 jbd_unlock_bh_journal_head(bh);
1874 return jh;
1877 static void __journal_remove_journal_head(struct buffer_head *bh)
1879 struct journal_head *jh = bh2jh(bh);
1881 J_ASSERT_JH(jh, jh->b_jcount >= 0);
1883 get_bh(bh);
1884 if (jh->b_jcount == 0) {
1885 if (jh->b_transaction == NULL &&
1886 jh->b_next_transaction == NULL &&
1887 jh->b_cp_transaction == NULL) {
1888 J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
1889 J_ASSERT_BH(bh, buffer_jbd(bh));
1890 J_ASSERT_BH(bh, jh2bh(jh) == bh);
1891 BUFFER_TRACE(bh, "remove journal_head");
1892 if (jh->b_frozen_data) {
1893 printk(KERN_WARNING "%s: freeing "
1894 "b_frozen_data\n",
1895 __FUNCTION__);
1896 jbd2_slab_free(jh->b_frozen_data, bh->b_size);
1898 if (jh->b_committed_data) {
1899 printk(KERN_WARNING "%s: freeing "
1900 "b_committed_data\n",
1901 __FUNCTION__);
1902 jbd2_slab_free(jh->b_committed_data, bh->b_size);
1904 bh->b_private = NULL;
1905 jh->b_bh = NULL; /* debug, really */
1906 clear_buffer_jbd(bh);
1907 __brelse(bh);
1908 journal_free_journal_head(jh);
1909 } else {
1910 BUFFER_TRACE(bh, "journal_head was locked");
1916 * jbd2_journal_remove_journal_head(): if the buffer isn't attached to a transaction
1917 * and has a zero b_jcount then remove and release its journal_head. If we did
1918 * see that the buffer is not used by any transaction we also "logically"
1919 * decrement ->b_count.
1921 * We in fact take an additional increment on ->b_count as a convenience,
1922 * because the caller usually wants to do additional things with the bh
1923 * after calling here.
1924 * The caller of jbd2_journal_remove_journal_head() *must* run __brelse(bh) at some
1925 * time. Once the caller has run __brelse(), the buffer is eligible for
1926 * reaping by try_to_free_buffers().
1928 void jbd2_journal_remove_journal_head(struct buffer_head *bh)
1930 jbd_lock_bh_journal_head(bh);
1931 __journal_remove_journal_head(bh);
1932 jbd_unlock_bh_journal_head(bh);
1936 * Drop a reference on the passed journal_head. If it fell to zero then try to
1937 * release the journal_head from the buffer_head.
1939 void jbd2_journal_put_journal_head(struct journal_head *jh)
1941 struct buffer_head *bh = jh2bh(jh);
1943 jbd_lock_bh_journal_head(bh);
1944 J_ASSERT_JH(jh, jh->b_jcount > 0);
1945 --jh->b_jcount;
1946 if (!jh->b_jcount && !jh->b_transaction) {
1947 __journal_remove_journal_head(bh);
1948 __brelse(bh);
1950 jbd_unlock_bh_journal_head(bh);
1954 * debugfs tunables
1956 #if defined(CONFIG_JBD2_DEBUG)
1957 u8 jbd2_journal_enable_debug;
1958 EXPORT_SYMBOL(jbd2_journal_enable_debug);
1959 #endif
1961 #if defined(CONFIG_JBD2_DEBUG) && defined(CONFIG_DEBUG_FS)
1963 #define JBD2_DEBUG_NAME "jbd2-debug"
1965 struct dentry *jbd2_debugfs_dir, *jbd2_debug;
1967 static void __init jbd2_create_debugfs_entry(void)
1969 jbd2_debugfs_dir = debugfs_create_dir("jbd2", NULL);
1970 if (jbd2_debugfs_dir)
1971 jbd2_debug = debugfs_create_u8(JBD2_DEBUG_NAME, S_IRUGO,
1972 jbd2_debugfs_dir,
1973 &jbd2_journal_enable_debug);
1976 static void __exit jbd2_remove_debugfs_entry(void)
1978 if (jbd2_debug)
1979 debugfs_remove(jbd2_debug);
1980 if (jbd2_debugfs_dir)
1981 debugfs_remove(jbd2_debugfs_dir);
1984 #else
1986 static void __init jbd2_create_debugfs_entry(void)
1988 do {
1989 } while (0);
1992 static void __exit jbd2_remove_debugfs_entry(void)
1994 do {
1995 } while (0);
1998 #endif
2000 struct kmem_cache *jbd2_handle_cache;
2002 static int __init journal_init_handle_cache(void)
2004 jbd2_handle_cache = kmem_cache_create("jbd2_journal_handle",
2005 sizeof(handle_t),
2006 0, /* offset */
2007 0, /* flags */
2008 NULL); /* ctor */
2009 if (jbd2_handle_cache == NULL) {
2010 printk(KERN_EMERG "JBD: failed to create handle cache\n");
2011 return -ENOMEM;
2013 return 0;
2016 static void jbd2_journal_destroy_handle_cache(void)
2018 if (jbd2_handle_cache)
2019 kmem_cache_destroy(jbd2_handle_cache);
2023 * Module startup and shutdown
2026 static int __init journal_init_caches(void)
2028 int ret;
2030 ret = jbd2_journal_init_revoke_caches();
2031 if (ret == 0)
2032 ret = journal_init_jbd2_journal_head_cache();
2033 if (ret == 0)
2034 ret = journal_init_handle_cache();
2035 return ret;
2038 static void jbd2_journal_destroy_caches(void)
2040 jbd2_journal_destroy_revoke_caches();
2041 jbd2_journal_destroy_jbd2_journal_head_cache();
2042 jbd2_journal_destroy_handle_cache();
2043 jbd2_journal_destroy_jbd_slabs();
2046 static int __init journal_init(void)
2048 int ret;
2050 BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
2052 ret = journal_init_caches();
2053 if (ret != 0)
2054 jbd2_journal_destroy_caches();
2055 jbd2_create_debugfs_entry();
2056 return ret;
2059 static void __exit journal_exit(void)
2061 #ifdef CONFIG_JBD2_DEBUG
2062 int n = atomic_read(&nr_journal_heads);
2063 if (n)
2064 printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n);
2065 #endif
2066 jbd2_remove_debugfs_entry();
2067 jbd2_journal_destroy_caches();
2070 MODULE_LICENSE("GPL");
2071 module_init(journal_init);
2072 module_exit(journal_exit);