journal.c 62.8 KB
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/*
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 * linux/fs/jbd2/journal.c
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 *
 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
 *
 * Copyright 1998 Red Hat corp --- All Rights Reserved
 *
 * This file is part of the Linux kernel and is made available under
 * the terms of the GNU General Public License, version 2, or at your
 * option, any later version, incorporated herein by reference.
 *
 * Generic filesystem journal-writing code; part of the ext2fs
 * journaling system.
 *
 * This file manages journals: areas of disk reserved for logging
 * transactional updates.  This includes the kernel journaling thread
 * which is responsible for scheduling updates to the log.
 *
 * We do not actually manage the physical storage of the journal in this
 * file: that is left to a per-journal policy function, which allows us
 * to store the journal within a filesystem-specified area for ext2
 * journaling (ext2 can use a reserved inode for storing the log).
 */

#include <linux/module.h>
#include <linux/time.h>
#include <linux/fs.h>
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#include <linux/jbd2.h>
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#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/mm.h>
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#include <linux/freezer.h>
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#include <linux/pagemap.h>
#include <linux/kthread.h>
#include <linux/poison.h>
#include <linux/proc_fs.h>
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#include <linux/debugfs.h>
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#include <linux/seq_file.h>
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#include <linux/math64.h>
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#include <linux/hash.h>

#define CREATE_TRACE_POINTS
#include <trace/events/jbd2.h>
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#include <asm/uaccess.h>
#include <asm/page.h>

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EXPORT_SYMBOL(jbd2_journal_start);
EXPORT_SYMBOL(jbd2_journal_restart);
EXPORT_SYMBOL(jbd2_journal_extend);
EXPORT_SYMBOL(jbd2_journal_stop);
EXPORT_SYMBOL(jbd2_journal_lock_updates);
EXPORT_SYMBOL(jbd2_journal_unlock_updates);
EXPORT_SYMBOL(jbd2_journal_get_write_access);
EXPORT_SYMBOL(jbd2_journal_get_create_access);
EXPORT_SYMBOL(jbd2_journal_get_undo_access);
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EXPORT_SYMBOL(jbd2_journal_set_triggers);
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EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
EXPORT_SYMBOL(jbd2_journal_release_buffer);
EXPORT_SYMBOL(jbd2_journal_forget);
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#if 0
EXPORT_SYMBOL(journal_sync_buffer);
#endif
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EXPORT_SYMBOL(jbd2_journal_flush);
EXPORT_SYMBOL(jbd2_journal_revoke);

EXPORT_SYMBOL(jbd2_journal_init_dev);
EXPORT_SYMBOL(jbd2_journal_init_inode);
EXPORT_SYMBOL(jbd2_journal_update_format);
EXPORT_SYMBOL(jbd2_journal_check_used_features);
EXPORT_SYMBOL(jbd2_journal_check_available_features);
EXPORT_SYMBOL(jbd2_journal_set_features);
EXPORT_SYMBOL(jbd2_journal_load);
EXPORT_SYMBOL(jbd2_journal_destroy);
EXPORT_SYMBOL(jbd2_journal_abort);
EXPORT_SYMBOL(jbd2_journal_errno);
EXPORT_SYMBOL(jbd2_journal_ack_err);
EXPORT_SYMBOL(jbd2_journal_clear_err);
EXPORT_SYMBOL(jbd2_log_wait_commit);
EXPORT_SYMBOL(jbd2_journal_start_commit);
EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
EXPORT_SYMBOL(jbd2_journal_wipe);
EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
EXPORT_SYMBOL(jbd2_journal_invalidatepage);
EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
EXPORT_SYMBOL(jbd2_journal_force_commit);
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EXPORT_SYMBOL(jbd2_journal_file_inode);
EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
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static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
static void __journal_abort_soft (journal_t *journal, int errno);

/*
 * Helper function used to manage commit timeouts
 */

static void commit_timeout(unsigned long __data)
{
	struct task_struct * p = (struct task_struct *) __data;

	wake_up_process(p);
}

/*
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 * kjournald2: The main thread function used to manage a logging device
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 * journal.
 *
 * This kernel thread is responsible for two things:
 *
 * 1) COMMIT:  Every so often we need to commit the current state of the
 *    filesystem to disk.  The journal thread is responsible for writing
 *    all of the metadata buffers to disk.
 *
 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
 *    of the data in that part of the log has been rewritten elsewhere on
 *    the disk.  Flushing these old buffers to reclaim space in the log is
 *    known as checkpointing, and this thread is responsible for that job.
 */

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static int kjournald2(void *arg)
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{
	journal_t *journal = arg;
	transaction_t *transaction;

	/*
	 * Set up an interval timer which can be used to trigger a commit wakeup
	 * after the commit interval expires
	 */
	setup_timer(&journal->j_commit_timer, commit_timeout,
			(unsigned long)current);

	/* Record that the journal thread is running */
	journal->j_task = current;
	wake_up(&journal->j_wait_done_commit);

	/*
	 * And now, wait forever for commit wakeup events.
	 */
	spin_lock(&journal->j_state_lock);

loop:
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	if (journal->j_flags & JBD2_UNMOUNT)
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		goto end_loop;

	jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
		journal->j_commit_sequence, journal->j_commit_request);

	if (journal->j_commit_sequence != journal->j_commit_request) {
		jbd_debug(1, "OK, requests differ\n");
		spin_unlock(&journal->j_state_lock);
		del_timer_sync(&journal->j_commit_timer);
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		jbd2_journal_commit_transaction(journal);
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		spin_lock(&journal->j_state_lock);
		goto loop;
	}

	wake_up(&journal->j_wait_done_commit);
	if (freezing(current)) {
		/*
		 * The simpler the better. Flushing journal isn't a
		 * good idea, because that depends on threads that may
		 * be already stopped.
		 */
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		jbd_debug(1, "Now suspending kjournald2\n");
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		spin_unlock(&journal->j_state_lock);
		refrigerator();
		spin_lock(&journal->j_state_lock);
	} else {
		/*
		 * We assume on resume that commits are already there,
		 * so we don't sleep
		 */
		DEFINE_WAIT(wait);
		int should_sleep = 1;

		prepare_to_wait(&journal->j_wait_commit, &wait,
				TASK_INTERRUPTIBLE);
		if (journal->j_commit_sequence != journal->j_commit_request)
			should_sleep = 0;
		transaction = journal->j_running_transaction;
		if (transaction && time_after_eq(jiffies,
						transaction->t_expires))
			should_sleep = 0;
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		if (journal->j_flags & JBD2_UNMOUNT)
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			should_sleep = 0;
		if (should_sleep) {
			spin_unlock(&journal->j_state_lock);
			schedule();
			spin_lock(&journal->j_state_lock);
		}
		finish_wait(&journal->j_wait_commit, &wait);
	}

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	jbd_debug(1, "kjournald2 wakes\n");
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	/*
	 * Were we woken up by a commit wakeup event?
	 */
	transaction = journal->j_running_transaction;
	if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
		journal->j_commit_request = transaction->t_tid;
		jbd_debug(1, "woke because of timeout\n");
	}
	goto loop;

end_loop:
	spin_unlock(&journal->j_state_lock);
	del_timer_sync(&journal->j_commit_timer);
	journal->j_task = NULL;
	wake_up(&journal->j_wait_done_commit);
	jbd_debug(1, "Journal thread exiting.\n");
	return 0;
}

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static int jbd2_journal_start_thread(journal_t *journal)
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{
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	struct task_struct *t;

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	t = kthread_run(kjournald2, journal, "jbd2/%s",
			journal->j_devname);
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	if (IS_ERR(t))
		return PTR_ERR(t);

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	wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
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	return 0;
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}

static void journal_kill_thread(journal_t *journal)
{
	spin_lock(&journal->j_state_lock);
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	journal->j_flags |= JBD2_UNMOUNT;
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	while (journal->j_task) {
		wake_up(&journal->j_wait_commit);
		spin_unlock(&journal->j_state_lock);
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		wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
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		spin_lock(&journal->j_state_lock);
	}
	spin_unlock(&journal->j_state_lock);
}

/*
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 * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
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 *
 * Writes a metadata buffer to a given disk block.  The actual IO is not
 * performed but a new buffer_head is constructed which labels the data
 * to be written with the correct destination disk block.
 *
 * Any magic-number escaping which needs to be done will cause a
 * copy-out here.  If the buffer happens to start with the
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 * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
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 * magic number is only written to the log for descripter blocks.  In
 * this case, we copy the data and replace the first word with 0, and we
 * return a result code which indicates that this buffer needs to be
 * marked as an escaped buffer in the corresponding log descriptor
 * block.  The missing word can then be restored when the block is read
 * during recovery.
 *
 * If the source buffer has already been modified by a new transaction
 * since we took the last commit snapshot, we use the frozen copy of
 * that data for IO.  If we end up using the existing buffer_head's data
 * for the write, then we *have* to lock the buffer to prevent anyone
 * else from using and possibly modifying it while the IO is in
 * progress.
 *
 * The function returns a pointer to the buffer_heads to be used for IO.
 *
 * We assume that the journal has already been locked in this function.
 *
 * Return value:
 *  <0: Error
 * >=0: Finished OK
 *
 * On success:
 * Bit 0 set == escape performed on the data
 * Bit 1 set == buffer copy-out performed (kfree the data after IO)
 */

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int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
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				  struct journal_head  *jh_in,
				  struct journal_head **jh_out,
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				  unsigned long long blocknr)
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{
	int need_copy_out = 0;
	int done_copy_out = 0;
	int do_escape = 0;
	char *mapped_data;
	struct buffer_head *new_bh;
	struct journal_head *new_jh;
	struct page *new_page;
	unsigned int new_offset;
	struct buffer_head *bh_in = jh2bh(jh_in);
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	struct jbd2_buffer_trigger_type *triggers;
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	journal_t *journal = transaction->t_journal;
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	/*
	 * The buffer really shouldn't be locked: only the current committing
	 * transaction is allowed to write it, so nobody else is allowed
	 * to do any IO.
	 *
	 * akpm: except if we're journalling data, and write() output is
	 * also part of a shared mapping, and another thread has
	 * decided to launch a writepage() against this buffer.
	 */
	J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));

	new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
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	/* keep subsequent assertions sane */
	new_bh->b_state = 0;
	init_buffer(new_bh, NULL, NULL);
	atomic_set(&new_bh->b_count, 1);
	new_jh = jbd2_journal_add_journal_head(new_bh);	/* This sleeps */
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	/*
	 * If a new transaction has already done a buffer copy-out, then
	 * we use that version of the data for the commit.
	 */
	jbd_lock_bh_state(bh_in);
repeat:
	if (jh_in->b_frozen_data) {
		done_copy_out = 1;
		new_page = virt_to_page(jh_in->b_frozen_data);
		new_offset = offset_in_page(jh_in->b_frozen_data);
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		triggers = jh_in->b_frozen_triggers;
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	} else {
		new_page = jh2bh(jh_in)->b_page;
		new_offset = offset_in_page(jh2bh(jh_in)->b_data);
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		triggers = jh_in->b_triggers;
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	}

	mapped_data = kmap_atomic(new_page, KM_USER0);
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	/*
	 * Fire any commit trigger.  Do this before checking for escaping,
	 * as the trigger may modify the magic offset.  If a copy-out
	 * happens afterwards, it will have the correct data in the buffer.
	 */
	jbd2_buffer_commit_trigger(jh_in, mapped_data + new_offset,
				   triggers);

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	/*
	 * Check for escaping
	 */
	if (*((__be32 *)(mapped_data + new_offset)) ==
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				cpu_to_be32(JBD2_MAGIC_NUMBER)) {
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		need_copy_out = 1;
		do_escape = 1;
	}
	kunmap_atomic(mapped_data, KM_USER0);

	/*
	 * Do we need to do a data copy?
	 */
	if (need_copy_out && !done_copy_out) {
		char *tmp;

		jbd_unlock_bh_state(bh_in);
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		tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
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		if (!tmp) {
			jbd2_journal_put_journal_head(new_jh);
			return -ENOMEM;
		}
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		jbd_lock_bh_state(bh_in);
		if (jh_in->b_frozen_data) {
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			jbd2_free(tmp, bh_in->b_size);
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			goto repeat;
		}

		jh_in->b_frozen_data = tmp;
		mapped_data = kmap_atomic(new_page, KM_USER0);
		memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size);
		kunmap_atomic(mapped_data, KM_USER0);

		new_page = virt_to_page(tmp);
		new_offset = offset_in_page(tmp);
		done_copy_out = 1;
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		/*
		 * This isn't strictly necessary, as we're using frozen
		 * data for the escaping, but it keeps consistency with
		 * b_frozen_data usage.
		 */
		jh_in->b_frozen_triggers = jh_in->b_triggers;
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	}

	/*
	 * Did we need to do an escaping?  Now we've done all the
	 * copying, we can finally do so.
	 */
	if (do_escape) {
		mapped_data = kmap_atomic(new_page, KM_USER0);
		*((unsigned int *)(mapped_data + new_offset)) = 0;
		kunmap_atomic(mapped_data, KM_USER0);
	}

	set_bh_page(new_bh, new_page, new_offset);
	new_jh->b_transaction = NULL;
	new_bh->b_size = jh2bh(jh_in)->b_size;
	new_bh->b_bdev = transaction->t_journal->j_dev;
	new_bh->b_blocknr = blocknr;
	set_buffer_mapped(new_bh);
	set_buffer_dirty(new_bh);

	*jh_out = new_jh;

	/*
	 * The to-be-written buffer needs to get moved to the io queue,
	 * and the original buffer whose contents we are shadowing or
	 * copying is moved to the transaction's shadow queue.
	 */
	JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
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	spin_lock(&journal->j_list_lock);
	__jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
	spin_unlock(&journal->j_list_lock);
	jbd_unlock_bh_state(bh_in);

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	JBUFFER_TRACE(new_jh, "file as BJ_IO");
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	jbd2_journal_file_buffer(new_jh, transaction, BJ_IO);
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	return do_escape | (done_copy_out << 1);
}

/*
 * Allocation code for the journal file.  Manage the space left in the
 * journal, so that we can begin checkpointing when appropriate.
 */

/*
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 * __jbd2_log_space_left: Return the number of free blocks left in the journal.
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 *
 * Called with the journal already locked.
 *
 * Called under j_state_lock
 */

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int __jbd2_log_space_left(journal_t *journal)
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{
	int left = journal->j_free;

	assert_spin_locked(&journal->j_state_lock);

	/*
	 * Be pessimistic here about the number of those free blocks which
	 * might be required for log descriptor control blocks.
	 */

#define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */

	left -= MIN_LOG_RESERVED_BLOCKS;

	if (left <= 0)
		return 0;
	left -= (left >> 3);
	return left;
}

/*
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 * Called under j_state_lock.  Returns true if a transaction commit was started.
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 */
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int __jbd2_log_start_commit(journal_t *journal, tid_t target)
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{
	/*
	 * Are we already doing a recent enough commit?
	 */
	if (!tid_geq(journal->j_commit_request, target)) {
		/*
		 * We want a new commit: OK, mark the request and wakup the
		 * commit thread.  We do _not_ do the commit ourselves.
		 */

		journal->j_commit_request = target;
		jbd_debug(1, "JBD: requesting commit %d/%d\n",
			  journal->j_commit_request,
			  journal->j_commit_sequence);
		wake_up(&journal->j_wait_commit);
		return 1;
	}
	return 0;
}

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int jbd2_log_start_commit(journal_t *journal, tid_t tid)
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{
	int ret;

	spin_lock(&journal->j_state_lock);
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	ret = __jbd2_log_start_commit(journal, tid);
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	spin_unlock(&journal->j_state_lock);
	return ret;
}

/*
 * Force and wait upon a commit if the calling process is not within
 * transaction.  This is used for forcing out undo-protected data which contains
 * bitmaps, when the fs is running out of space.
 *
 * We can only force the running transaction if we don't have an active handle;
 * otherwise, we will deadlock.
 *
 * Returns true if a transaction was started.
 */
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int jbd2_journal_force_commit_nested(journal_t *journal)
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{
	transaction_t *transaction = NULL;
	tid_t tid;

	spin_lock(&journal->j_state_lock);
	if (journal->j_running_transaction && !current->journal_info) {
		transaction = journal->j_running_transaction;
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		__jbd2_log_start_commit(journal, transaction->t_tid);
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	} else if (journal->j_committing_transaction)
		transaction = journal->j_committing_transaction;

	if (!transaction) {
		spin_unlock(&journal->j_state_lock);
		return 0;	/* Nothing to retry */
	}

	tid = transaction->t_tid;
	spin_unlock(&journal->j_state_lock);
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	jbd2_log_wait_commit(journal, tid);
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	return 1;
}

/*
 * Start a commit of the current running transaction (if any).  Returns true
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 * if a transaction is going to be committed (or is currently already
 * committing), and fills its tid in at *ptid
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 */
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int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
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{
	int ret = 0;

	spin_lock(&journal->j_state_lock);
	if (journal->j_running_transaction) {
		tid_t tid = journal->j_running_transaction->t_tid;

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		__jbd2_log_start_commit(journal, tid);
		/* There's a running transaction and we've just made sure
		 * it's commit has been scheduled. */
		if (ptid)
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			*ptid = tid;
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		ret = 1;
	} else if (journal->j_committing_transaction) {
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		/*
		 * If ext3_write_super() recently started a commit, then we
		 * have to wait for completion of that transaction
		 */
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		if (ptid)
			*ptid = journal->j_committing_transaction->t_tid;
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		ret = 1;
	}
	spin_unlock(&journal->j_state_lock);
	return ret;
}

/*
 * Wait for a specified commit to complete.
 * The caller may not hold the journal lock.
 */
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int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
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{
	int err = 0;

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#ifdef CONFIG_JBD2_DEBUG
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	spin_lock(&journal->j_state_lock);
	if (!tid_geq(journal->j_commit_request, tid)) {
		printk(KERN_EMERG
		       "%s: error: j_commit_request=%d, tid=%d\n",
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		       __func__, journal->j_commit_request, tid);
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	}
	spin_unlock(&journal->j_state_lock);
#endif
	spin_lock(&journal->j_state_lock);
	while (tid_gt(tid, journal->j_commit_sequence)) {
		jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n",
				  tid, journal->j_commit_sequence);
		wake_up(&journal->j_wait_commit);
		spin_unlock(&journal->j_state_lock);
		wait_event(journal->j_wait_done_commit,
				!tid_gt(tid, journal->j_commit_sequence));
		spin_lock(&journal->j_state_lock);
	}
	spin_unlock(&journal->j_state_lock);

	if (unlikely(is_journal_aborted(journal))) {
		printk(KERN_EMERG "journal commit I/O error\n");
		err = -EIO;
	}
	return err;
}

/*
 * Log buffer allocation routines:
 */

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int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
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{
	unsigned long blocknr;

	spin_lock(&journal->j_state_lock);
	J_ASSERT(journal->j_free > 1);

	blocknr = journal->j_head;
	journal->j_head++;
	journal->j_free--;
	if (journal->j_head == journal->j_last)
		journal->j_head = journal->j_first;
	spin_unlock(&journal->j_state_lock);
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	return jbd2_journal_bmap(journal, blocknr, retp);
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}

/*
 * Conversion of logical to physical block numbers for the journal
 *
 * On external journals the journal blocks are identity-mapped, so
 * this is a no-op.  If needed, we can use j_blk_offset - everything is
 * ready.
 */
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int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
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		 unsigned long long *retp)
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{
	int err = 0;
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	unsigned long long ret;
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	if (journal->j_inode) {
		ret = bmap(journal->j_inode, blocknr);
		if (ret)
			*retp = ret;
		else {
			printk(KERN_ALERT "%s: journal block not found "
					"at offset %lu on %s\n",
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			       __func__, blocknr, journal->j_devname);
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			err = -EIO;
			__journal_abort_soft(journal, err);
		}
	} else {
		*retp = blocknr; /* +journal->j_blk_offset */
	}
	return err;
}

/*
 * We play buffer_head aliasing tricks to write data/metadata blocks to
 * the journal without copying their contents, but for journal
 * descriptor blocks we do need to generate bona fide buffers.
 *
649
 * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
650 651 652 653
 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
 * But we don't bother doing that, so there will be coherency problems with
 * mmaps of blockdevs which hold live JBD-controlled filesystems.
 */
654
struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
655 656
{
	struct buffer_head *bh;
657
	unsigned long long blocknr;
658 659
	int err;

660
	err = jbd2_journal_next_log_block(journal, &blocknr);
661 662 663 664 665

	if (err)
		return NULL;

	bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
666 667
	if (!bh)
		return NULL;
668 669 670 671 672
	lock_buffer(bh);
	memset(bh->b_data, 0, journal->j_blocksize);
	set_buffer_uptodate(bh);
	unlock_buffer(bh);
	BUFFER_TRACE(bh, "return this buffer");
673
	return jbd2_journal_add_journal_head(bh);
674 675
}

676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698
struct jbd2_stats_proc_session {
	journal_t *journal;
	struct transaction_stats_s *stats;
	int start;
	int max;
};

static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
{
	return *pos ? NULL : SEQ_START_TOKEN;
}

static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
{
	return NULL;
}

static int jbd2_seq_info_show(struct seq_file *seq, void *v)
{
	struct jbd2_stats_proc_session *s = seq->private;

	if (v != SEQ_START_TOKEN)
		return 0;
699
	seq_printf(seq, "%lu transaction, each up to %u blocks\n",
700 701 702 703 704
			s->stats->ts_tid,
			s->journal->j_max_transaction_buffers);
	if (s->stats->ts_tid == 0)
		return 0;
	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));
714 715
	seq_printf(seq, "  %lluus average transaction commit time\n",
		   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);
722 723 724 725 726 727 728
	return 0;
}

static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
{
}

J
James Morris 已提交
729
static const struct seq_operations jbd2_seq_info_ops = {
730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776
	.start  = jbd2_seq_info_start,
	.next   = jbd2_seq_info_next,
	.stop   = jbd2_seq_info_stop,
	.show   = jbd2_seq_info_show,
};

static int jbd2_seq_info_open(struct inode *inode, struct file *file)
{
	journal_t *journal = PDE(inode)->data;
	struct jbd2_stats_proc_session *s;
	int rc, size;

	s = kmalloc(sizeof(*s), GFP_KERNEL);
	if (s == NULL)
		return -ENOMEM;
	size = sizeof(struct transaction_stats_s);
	s->stats = kmalloc(size, GFP_KERNEL);
	if (s->stats == NULL) {
		kfree(s);
		return -ENOMEM;
	}
	spin_lock(&journal->j_history_lock);
	memcpy(s->stats, &journal->j_stats, size);
	s->journal = journal;
	spin_unlock(&journal->j_history_lock);

	rc = seq_open(file, &jbd2_seq_info_ops);
	if (rc == 0) {
		struct seq_file *m = file->private_data;
		m->private = s;
	} else {
		kfree(s->stats);
		kfree(s);
	}
	return rc;

}

static int jbd2_seq_info_release(struct inode *inode, struct file *file)
{
	struct seq_file *seq = file->private_data;
	struct jbd2_stats_proc_session *s = seq->private;
	kfree(s->stats);
	kfree(s);
	return seq_release(inode, file);
}

777
static const struct file_operations jbd2_seq_info_fops = {
778 779 780 781 782 783 784 785 786 787 788
	.owner		= THIS_MODULE,
	.open           = jbd2_seq_info_open,
	.read           = seq_read,
	.llseek         = seq_lseek,
	.release        = jbd2_seq_info_release,
};

static struct proc_dir_entry *proc_jbd2_stats;

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) {
791 792
		proc_create_data("info", S_IRUGO, journal->j_proc_entry,
				 &jbd2_seq_info_fops, journal);
793 794 795 796 797 798
	}
}

static void jbd2_stats_proc_exit(journal_t *journal)
{
	remove_proc_entry("info", journal->j_proc_entry);
799
	remove_proc_entry(journal->j_devname, proc_jbd2_stats);
800 801
}

802 803 804 805 806 807 808 809 810 811 812 813 814 815
/*
 * Management for journal control blocks: functions to create and
 * destroy journal_t structures, and to initialise and read existing
 * journal blocks from disk.  */

/* First: create and setup a journal_t object in memory.  We initialise
 * very few fields yet: that has to wait until we have created the
 * journal structures from from scratch, or loaded them from disk. */

static journal_t * journal_init_common (void)
{
	journal_t *journal;
	int err;

816
	journal = kzalloc(sizeof(*journal), GFP_KERNEL|__GFP_NOFAIL);
817 818 819 820 821 822 823 824 825 826 827 828 829 830 831
	if (!journal)
		goto fail;

	init_waitqueue_head(&journal->j_wait_transaction_locked);
	init_waitqueue_head(&journal->j_wait_logspace);
	init_waitqueue_head(&journal->j_wait_done_commit);
	init_waitqueue_head(&journal->j_wait_checkpoint);
	init_waitqueue_head(&journal->j_wait_commit);
	init_waitqueue_head(&journal->j_wait_updates);
	mutex_init(&journal->j_barrier);
	mutex_init(&journal->j_checkpoint_mutex);
	spin_lock_init(&journal->j_revoke_lock);
	spin_lock_init(&journal->j_list_lock);
	spin_lock_init(&journal->j_state_lock);

832
	journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
833 834
	journal->j_min_batch_time = 0;
	journal->j_max_batch_time = 15000; /* 15ms */
835 836

	/* The journal is marked for error until we succeed with recovery! */
837
	journal->j_flags = JBD2_ABORT;
838 839

	/* Set up a default-sized revoke table for the new mount. */
840
	err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
841 842 843 844
	if (err) {
		kfree(journal);
		goto fail;
	}
845

846
	spin_lock_init(&journal->j_history_lock);
847

848 849 850 851 852
	return journal;
fail:
	return NULL;
}

853
/* jbd2_journal_init_dev and jbd2_journal_init_inode:
854 855 856 857 858 859 860 861 862
 *
 * Create a journal structure assigned some fixed set of disk blocks to
 * the journal.  We don't actually touch those disk blocks yet, but we
 * need to set up all of the mapping information to tell the journaling
 * system where the journal blocks are.
 *
 */

/**
R
Randy Dunlap 已提交
863
 *  journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
864 865 866 867 868
 *  @bdev: Block device on which to create the journal
 *  @fs_dev: Device which hold journalled filesystem for this journal.
 *  @start: Block nr Start of journal.
 *  @len:  Length of the journal in blocks.
 *  @blocksize: blocksize of journalling device
R
Randy Dunlap 已提交
869 870
 *
 *  Returns: a newly created journal_t *
871
 *
872
 *  jbd2_journal_init_dev creates a journal which maps a fixed contiguous
873 874 875
 *  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)
879 880 881
{
	journal_t *journal = journal_init_common();
	struct buffer_head *bh;
882
	char *p;
883 884 885 886 887 888 889
	int n;

	if (!journal)
		return NULL;

	/* journal descriptor can store up to n blocks -bzzz */
	journal->j_blocksize = blocksize;
890
	jbd2_stats_proc_init(journal);
891 892 893 894 895
	n = journal->j_blocksize / sizeof(journal_block_tag_t);
	journal->j_wbufsize = n;
	journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
	if (!journal->j_wbuf) {
		printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
896
			__func__);
897
		goto out_err;
898 899 900 901 902
	}
	journal->j_dev = bdev;
	journal->j_fs_dev = fs_dev;
	journal->j_blk_offset = start;
	journal->j_maxlen = len;
903 904 905 906
	bdevname(journal->j_dev, journal->j_devname);
	p = journal->j_devname;
	while ((p = strchr(p, '/')))
		*p = '!';
907 908

	bh = __getblk(journal->j_dev, start, journal->j_blocksize);
909 910 911 912 913 914
	if (!bh) {
		printk(KERN_ERR
		       "%s: Cannot get buffer for journal superblock\n",
		       __func__);
		goto out_err;
	}
915 916
	journal->j_sb_buffer = bh;
	journal->j_superblock = (journal_superblock_t *)bh->b_data;
917

918
	return journal;
919
out_err:
920
	kfree(journal->j_wbuf);
921 922 923
	jbd2_stats_proc_exit(journal);
	kfree(journal);
	return NULL;
924 925 926
}

/**
927
 *  journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
928 929
 *  @inode: An inode to create the journal in
 *
930
 * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
931 932 933
 * the journal.  The inode must exist already, must support bmap() and
 * must have all data blocks preallocated.
 */
934
journal_t * jbd2_journal_init_inode (struct inode *inode)
935 936 937
{
	struct buffer_head *bh;
	journal_t *journal = journal_init_common();
938
	char *p;
939 940
	int err;
	int n;
941
	unsigned long long blocknr;
942 943 944 945 946 947

	if (!journal)
		return NULL;

	journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
	journal->j_inode = inode;
948 949 950 951 952
	bdevname(journal->j_dev, journal->j_devname);
	p = journal->j_devname;
	while ((p = strchr(p, '/')))
		*p = '!';
	p = journal->j_devname + strlen(journal->j_devname);
953
	sprintf(p, "-%lu", journal->j_inode->i_ino);
954 955 956 957 958 959 960 961
	jbd_debug(1,
		  "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
		  journal, inode->i_sb->s_id, inode->i_ino,
		  (long long) inode->i_size,
		  inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);

	journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
	journal->j_blocksize = inode->i_sb->s_blocksize;
962
	jbd2_stats_proc_init(journal);
963 964 965 966 967 968 969

	/* journal descriptor can store up to n blocks -bzzz */
	n = journal->j_blocksize / sizeof(journal_block_tag_t);
	journal->j_wbufsize = n;
	journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
	if (!journal->j_wbuf) {
		printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
970
			__func__);
971
		goto out_err;
972 973
	}

974
	err = jbd2_journal_bmap(journal, 0, &blocknr);
975 976 977
	/* If that failed, give up */
	if (err) {
		printk(KERN_ERR "%s: Cannnot locate journal superblock\n",
978
		       __func__);
979
		goto out_err;
980 981 982
	}

	bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
983 984 985 986 987 988
	if (!bh) {
		printk(KERN_ERR
		       "%s: Cannot get buffer for journal superblock\n",
		       __func__);
		goto out_err;
	}
989 990 991 992
	journal->j_sb_buffer = bh;
	journal->j_superblock = (journal_superblock_t *)bh->b_data;

	return journal;
993
out_err:
994
	kfree(journal->j_wbuf);
995 996 997
	jbd2_stats_proc_exit(journal);
	kfree(journal);
	return NULL;
998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021
}

/*
 * If the journal init or create aborts, we need to mark the journal
 * superblock as being NULL to prevent the journal destroy from writing
 * back a bogus superblock.
 */
static void journal_fail_superblock (journal_t *journal)
{
	struct buffer_head *bh = journal->j_sb_buffer;
	brelse(bh);
	journal->j_sb_buffer = NULL;
}

/*
 * Given a journal_t structure, initialise the various fields for
 * startup of a new journaling session.  We use this both when creating
 * a journal, and after recovering an old journal to reset it for
 * subsequent use.
 */

static int journal_reset(journal_t *journal)
{
	journal_superblock_t *sb = journal->j_superblock;
1022
	unsigned long long first, last;
1023 1024 1025

	first = be32_to_cpu(sb->s_first);
	last = be32_to_cpu(sb->s_maxlen);
1026 1027 1028 1029 1030 1031
	if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
		printk(KERN_ERR "JBD: Journal too short (blocks %llu-%llu).\n",
		       first, last);
		journal_fail_superblock(journal);
		return -EINVAL;
	}
1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046

	journal->j_first = first;
	journal->j_last = last;

	journal->j_head = first;
	journal->j_tail = first;
	journal->j_free = last - first;

	journal->j_tail_sequence = journal->j_transaction_sequence;
	journal->j_commit_sequence = journal->j_transaction_sequence - 1;
	journal->j_commit_request = journal->j_commit_sequence;

	journal->j_max_transaction_buffers = journal->j_maxlen / 4;

	/* Add the dynamic fields and write it to disk. */
1047
	jbd2_journal_update_superblock(journal, 1);
1048
	return jbd2_journal_start_thread(journal);
1049 1050 1051
}

/**
1052
 * void jbd2_journal_update_superblock() - Update journal sb on disk.
1053 1054 1055 1056 1057 1058
 * @journal: The journal to update.
 * @wait: Set to '0' if you don't want to wait for IO completion.
 *
 * Update a journal's dynamic superblock fields and write it to disk,
 * optionally waiting for the IO to complete.
 */
1059
void jbd2_journal_update_superblock(journal_t *journal, int wait)
1060 1061 1062 1063 1064 1065 1066 1067
{
	journal_superblock_t *sb = journal->j_superblock;
	struct buffer_head *bh = journal->j_sb_buffer;

	/*
	 * As a special case, if the on-disk copy is already marked as needing
	 * no recovery (s_start == 0) and there are no outstanding transactions
	 * in the filesystem, then we can safely defer the superblock update
1068
	 * until the next commit by setting JBD2_FLUSHED.  This avoids
1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079
	 * attempting a write to a potential-readonly device.
	 */
	if (sb->s_start == 0 && journal->j_tail_sequence ==
				journal->j_transaction_sequence) {
		jbd_debug(1,"JBD: Skipping superblock update on recovered sb "
			"(start %ld, seq %d, errno %d)\n",
			journal->j_tail, journal->j_tail_sequence,
			journal->j_errno);
		goto out;
	}

1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095
	if (buffer_write_io_error(bh)) {
		/*
		 * Oh, dear.  A previous attempt to write the journal
		 * superblock failed.  This could happen because the
		 * USB device was yanked out.  Or it could happen to
		 * be a transient write error and maybe the block will
		 * be remapped.  Nothing we can do but to retry the
		 * write and hope for the best.
		 */
		printk(KERN_ERR "JBD2: previous I/O error detected "
		       "for journal superblock update for %s.\n",
		       journal->j_devname);
		clear_buffer_write_io_error(bh);
		set_buffer_uptodate(bh);
	}

1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106
	spin_lock(&journal->j_state_lock);
	jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n",
		  journal->j_tail, journal->j_tail_sequence, journal->j_errno);

	sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
	sb->s_start    = cpu_to_be32(journal->j_tail);
	sb->s_errno    = cpu_to_be32(journal->j_errno);
	spin_unlock(&journal->j_state_lock);

	BUFFER_TRACE(bh, "marking dirty");
	mark_buffer_dirty(bh);
1107
	if (wait) {
1108
		sync_dirty_buffer(bh);
1109 1110 1111 1112 1113 1114 1115 1116
		if (buffer_write_io_error(bh)) {
			printk(KERN_ERR "JBD2: I/O error detected "
			       "when updating journal superblock for %s.\n",
			       journal->j_devname);
			clear_buffer_write_io_error(bh);
			set_buffer_uptodate(bh);
		}
	} else
1117 1118 1119 1120 1121 1122 1123 1124 1125
		ll_rw_block(SWRITE, 1, &bh);

out:
	/* If we have just flushed the log (by marking s_start==0), then
	 * any future commit will have to be careful to update the
	 * superblock again to re-record the true start of the log. */

	spin_lock(&journal->j_state_lock);
	if (sb->s_start)
1126
		journal->j_flags &= ~JBD2_FLUSHED;
1127
	else
1128
		journal->j_flags |= JBD2_FLUSHED;
1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159
	spin_unlock(&journal->j_state_lock);
}

/*
 * Read the superblock for a given journal, performing initial
 * validation of the format.
 */

static int journal_get_superblock(journal_t *journal)
{
	struct buffer_head *bh;
	journal_superblock_t *sb;
	int err = -EIO;

	bh = journal->j_sb_buffer;

	J_ASSERT(bh != NULL);
	if (!buffer_uptodate(bh)) {
		ll_rw_block(READ, 1, &bh);
		wait_on_buffer(bh);
		if (!buffer_uptodate(bh)) {
			printk (KERN_ERR
				"JBD: IO error reading journal superblock\n");
			goto out;
		}
	}

	sb = journal->j_superblock;

	err = -EINVAL;

1160
	if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1161 1162 1163 1164 1165 1166
	    sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
		printk(KERN_WARNING "JBD: no valid journal superblock found\n");
		goto out;
	}

	switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1167
	case JBD2_SUPERBLOCK_V1:
1168 1169
		journal->j_format_version = 1;
		break;
1170
	case JBD2_SUPERBLOCK_V2:
1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218
		journal->j_format_version = 2;
		break;
	default:
		printk(KERN_WARNING "JBD: unrecognised superblock format ID\n");
		goto out;
	}

	if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
		journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
	else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
		printk (KERN_WARNING "JBD: journal file too short\n");
		goto out;
	}

	return 0;

out:
	journal_fail_superblock(journal);
	return err;
}

/*
 * Load the on-disk journal superblock and read the key fields into the
 * journal_t.
 */

static int load_superblock(journal_t *journal)
{
	int err;
	journal_superblock_t *sb;

	err = journal_get_superblock(journal);
	if (err)
		return err;

	sb = journal->j_superblock;

	journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
	journal->j_tail = be32_to_cpu(sb->s_start);
	journal->j_first = be32_to_cpu(sb->s_first);
	journal->j_last = be32_to_cpu(sb->s_maxlen);
	journal->j_errno = be32_to_cpu(sb->s_errno);

	return 0;
}


/**
1219
 * int jbd2_journal_load() - Read journal from disk.
1220 1221 1222 1223 1224 1225
 * @journal: Journal to act on.
 *
 * Given a journal_t structure which tells us which disk blocks contain
 * a journal, read the journal from disk to initialise the in-memory
 * structures.
 */
1226
int jbd2_journal_load(journal_t *journal)
1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240
{
	int err;
	journal_superblock_t *sb;

	err = load_superblock(journal);
	if (err)
		return err;

	sb = journal->j_superblock;
	/* If this is a V2 superblock, then we have to check the
	 * features flags on it. */

	if (journal->j_format_version >= 2) {
		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 1245 1246 1247 1248 1249 1250 1251
			printk (KERN_WARNING
				"JBD: Unrecognised features on journal\n");
			return -EINVAL;
		}
	}

	/* Let the recovery code check whether it needs to recover any
	 * data from the journal. */
1252
	if (jbd2_journal_recover(journal))
1253 1254
		goto recovery_error;

1255 1256 1257 1258 1259 1260 1261
	if (journal->j_failed_commit) {
		printk(KERN_ERR "JBD2: journal transaction %u on %s "
		       "is corrupt.\n", journal->j_failed_commit,
		       journal->j_devname);
		return -EIO;
	}

1262 1263 1264 1265 1266 1267
	/* OK, we've finished with the dynamic journal bits:
	 * reinitialise the dynamic contents of the superblock in memory
	 * and reset them on disk. */
	if (journal_reset(journal))
		goto recovery_error;

1268 1269
	journal->j_flags &= ~JBD2_ABORT;
	journal->j_flags |= JBD2_LOADED;
1270 1271 1272 1273 1274 1275 1276 1277
	return 0;

recovery_error:
	printk (KERN_WARNING "JBD: recovery failed\n");
	return -EIO;
}

/**
1278
 * void jbd2_journal_destroy() - Release a journal_t structure.
1279 1280 1281 1282
 * @journal: Journal to act on.
 *
 * Release a journal_t structure once it is no longer in use by the
 * journaled object.
1283
 * Return <0 if we couldn't clean up the journal.
1284
 */
1285
int jbd2_journal_destroy(journal_t *journal)
1286
{
1287 1288
	int err = 0;

1289 1290 1291 1292 1293
	/* Wait for the commit thread to wake up and die. */
	journal_kill_thread(journal);

	/* Force a final log commit */
	if (journal->j_running_transaction)
1294
		jbd2_journal_commit_transaction(journal);
1295 1296 1297 1298 1299 1300 1301

	/* Force any old transactions to disk */

	/* Totally anal locking here... */
	spin_lock(&journal->j_list_lock);
	while (journal->j_checkpoint_transactions != NULL) {
		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 1306 1307 1308 1309 1310 1311 1312 1313
		spin_lock(&journal->j_list_lock);
	}

	J_ASSERT(journal->j_running_transaction == NULL);
	J_ASSERT(journal->j_committing_transaction == NULL);
	J_ASSERT(journal->j_checkpoint_transactions == NULL);
	spin_unlock(&journal->j_list_lock);

	if (journal->j_sb_buffer) {
1314 1315 1316 1317 1318 1319 1320 1321 1322
		if (!is_journal_aborted(journal)) {
			/* We can now mark the journal as empty. */
			journal->j_tail = 0;
			journal->j_tail_sequence =
				++journal->j_transaction_sequence;
			jbd2_journal_update_superblock(journal, 1);
		} else {
			err = -EIO;
		}
1323 1324 1325
		brelse(journal->j_sb_buffer);
	}

1326 1327
	if (journal->j_proc_entry)
		jbd2_stats_proc_exit(journal);
1328 1329 1330
	if (journal->j_inode)
		iput(journal->j_inode);
	if (journal->j_revoke)
1331
		jbd2_journal_destroy_revoke(journal);
1332 1333
	kfree(journal->j_wbuf);
	kfree(journal);
1334 1335

	return err;
1336 1337 1338 1339
}


/**
1340
 *int jbd2_journal_check_used_features () - Check if features specified are used.
1341 1342 1343 1344 1345 1346 1347 1348 1349
 * @journal: Journal to check.
 * @compat: bitmask of compatible features
 * @ro: bitmask of features that force read-only mount
 * @incompat: bitmask of incompatible features
 *
 * Check whether the journal uses all of a given set of
 * features.  Return true (non-zero) if it does.
 **/

1350
int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,
1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370
				 unsigned long ro, unsigned long incompat)
{
	journal_superblock_t *sb;

	if (!compat && !ro && !incompat)
		return 1;
	if (journal->j_format_version == 1)
		return 0;

	sb = journal->j_superblock;

	if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
	    ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
	    ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
		return 1;

	return 0;
}

/**
1371
 * int jbd2_journal_check_available_features() - Check feature set in journalling layer
1372 1373 1374 1375 1376 1377 1378 1379 1380
 * @journal: Journal to check.
 * @compat: bitmask of compatible features
 * @ro: bitmask of features that force read-only mount
 * @incompat: bitmask of incompatible features
 *
 * Check whether the journaling code supports the use of
 * all of a given set of features on this journal.  Return true
 * (non-zero) if it can. */

1381
int jbd2_journal_check_available_features (journal_t *journal, unsigned long compat,
1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397
				      unsigned long ro, unsigned long incompat)
{
	journal_superblock_t *sb;

	if (!compat && !ro && !incompat)
		return 1;

	sb = journal->j_superblock;

	/* We can support any known requested features iff the
	 * superblock is in version 2.  Otherwise we fail to support any
	 * extended sb features. */

	if (journal->j_format_version != 2)
		return 0;

1398 1399 1400
	if ((compat   & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
	    (ro       & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
	    (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
1401 1402 1403 1404 1405 1406
		return 1;

	return 0;
}

/**
1407
 * int jbd2_journal_set_features () - Mark a given journal feature in the superblock
1408 1409 1410 1411 1412 1413 1414 1415 1416 1417
 * @journal: Journal to act on.
 * @compat: bitmask of compatible features
 * @ro: bitmask of features that force read-only mount
 * @incompat: bitmask of incompatible features
 *
 * Mark a given journal feature as present on the
 * superblock.  Returns true if the requested features could be set.
 *
 */

1418
int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
1419 1420 1421 1422
			  unsigned long ro, unsigned long incompat)
{
	journal_superblock_t *sb;

1423
	if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
1424 1425
		return 1;

1426
	if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440
		return 0;

	jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
		  compat, ro, incompat);

	sb = journal->j_superblock;

	sb->s_feature_compat    |= cpu_to_be32(compat);
	sb->s_feature_ro_compat |= cpu_to_be32(ro);
	sb->s_feature_incompat  |= cpu_to_be32(incompat);

	return 1;
}

1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466
/*
 * jbd2_journal_clear_features () - Clear a given journal feature in the
 * 				    superblock
 * @journal: Journal to act on.
 * @compat: bitmask of compatible features
 * @ro: bitmask of features that force read-only mount
 * @incompat: bitmask of incompatible features
 *
 * Clear a given journal feature as present on the
 * superblock.
 */
void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
				unsigned long ro, unsigned long incompat)
{
	journal_superblock_t *sb;

	jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
		  compat, ro, incompat);

	sb = journal->j_superblock;

	sb->s_feature_compat    &= ~cpu_to_be32(compat);
	sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
	sb->s_feature_incompat  &= ~cpu_to_be32(incompat);
}
EXPORT_SYMBOL(jbd2_journal_clear_features);
1467 1468

/**
1469
 * int jbd2_journal_update_format () - Update on-disk journal structure.
1470 1471 1472 1473 1474
 * @journal: Journal to act on.
 *
 * Given an initialised but unloaded journal struct, poke about in the
 * on-disk structure to update it to the most recent supported version.
 */
1475
int jbd2_journal_update_format (journal_t *journal)
1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486
{
	journal_superblock_t *sb;
	int err;

	err = journal_get_superblock(journal);
	if (err)
		return err;

	sb = journal->j_superblock;

	switch (be32_to_cpu(sb->s_header.h_blocktype)) {
1487
	case JBD2_SUPERBLOCK_V2:
1488
		return 0;
1489
	case JBD2_SUPERBLOCK_V1:
1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511
		return journal_convert_superblock_v1(journal, sb);
	default:
		break;
	}
	return -EINVAL;
}

static int journal_convert_superblock_v1(journal_t *journal,
					 journal_superblock_t *sb)
{
	int offset, blocksize;
	struct buffer_head *bh;

	printk(KERN_WARNING
		"JBD: Converting superblock from version 1 to 2.\n");

	/* Pre-initialise new fields to zero */
	offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
	blocksize = be32_to_cpu(sb->s_blocksize);
	memset(&sb->s_feature_compat, 0, blocksize-offset);

	sb->s_nr_users = cpu_to_be32(1);
1512
	sb->s_header.h_blocktype = cpu_to_be32(JBD2_SUPERBLOCK_V2);
1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523
	journal->j_format_version = 2;

	bh = journal->j_sb_buffer;
	BUFFER_TRACE(bh, "marking dirty");
	mark_buffer_dirty(bh);
	sync_dirty_buffer(bh);
	return 0;
}


/**
1524
 * int jbd2_journal_flush () - Flush journal
1525 1526 1527 1528 1529 1530 1531
 * @journal: Journal to act on.
 *
 * Flush all data for a given journal to disk and empty the journal.
 * Filesystems can use this when remounting readonly to ensure that
 * recovery does not need to happen on remount.
 */

1532
int jbd2_journal_flush(journal_t *journal)
1533 1534 1535 1536 1537 1538 1539 1540 1541 1542
{
	int err = 0;
	transaction_t *transaction = NULL;
	unsigned long old_tail;

	spin_lock(&journal->j_state_lock);

	/* Force everything buffered to the log... */
	if (journal->j_running_transaction) {
		transaction = journal->j_running_transaction;
1543
		__jbd2_log_start_commit(journal, transaction->t_tid);
1544 1545 1546 1547 1548 1549 1550 1551
	} else if (journal->j_committing_transaction)
		transaction = journal->j_committing_transaction;

	/* Wait for the log commit to complete... */
	if (transaction) {
		tid_t tid = transaction->t_tid;

		spin_unlock(&journal->j_state_lock);
1552
		jbd2_log_wait_commit(journal, tid);
1553 1554 1555 1556 1557 1558 1559 1560
	} else {
		spin_unlock(&journal->j_state_lock);
	}

	/* ...and flush everything in the log out to disk. */
	spin_lock(&journal->j_list_lock);
	while (!err && journal->j_checkpoint_transactions != NULL) {
		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 1565 1566
		spin_lock(&journal->j_list_lock);
	}
	spin_unlock(&journal->j_list_lock);
1567 1568 1569 1570

	if (is_journal_aborted(journal))
		return -EIO;

1571
	jbd2_cleanup_journal_tail(journal);
1572 1573 1574 1575 1576 1577 1578 1579 1580 1581

	/* Finally, mark the journal as really needing no recovery.
	 * This sets s_start==0 in the underlying superblock, which is
	 * the magic code for a fully-recovered superblock.  Any future
	 * commits of data to the journal will restore the current
	 * s_start value. */
	spin_lock(&journal->j_state_lock);
	old_tail = journal->j_tail;
	journal->j_tail = 0;
	spin_unlock(&journal->j_state_lock);
1582
	jbd2_journal_update_superblock(journal, 1);
1583 1584 1585 1586 1587 1588 1589 1590 1591
	spin_lock(&journal->j_state_lock);
	journal->j_tail = old_tail;

	J_ASSERT(!journal->j_running_transaction);
	J_ASSERT(!journal->j_committing_transaction);
	J_ASSERT(!journal->j_checkpoint_transactions);
	J_ASSERT(journal->j_head == journal->j_tail);
	J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
	spin_unlock(&journal->j_state_lock);
1592
	return 0;
1593 1594 1595
}

/**
1596
 * int jbd2_journal_wipe() - Wipe journal contents
1597 1598 1599 1600 1601
 * @journal: Journal to act on.
 * @write: flag (see below)
 *
 * Wipe out all of the contents of a journal, safely.  This will produce
 * a warning if the journal contains any valid recovery information.
1602
 * Must be called between journal_init_*() and jbd2_journal_load().
1603 1604 1605 1606 1607
 *
 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
 * we merely suppress recovery.
 */

1608
int jbd2_journal_wipe(journal_t *journal, int write)
1609 1610 1611 1612
{
	journal_superblock_t *sb;
	int err = 0;

1613
	J_ASSERT (!(journal->j_flags & JBD2_LOADED));
1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626

	err = load_superblock(journal);
	if (err)
		return err;

	sb = journal->j_superblock;

	if (!journal->j_tail)
		goto no_recovery;

	printk (KERN_WARNING "JBD: %s recovery information on journal\n",
		write ? "Clearing" : "Ignoring");

1627
	err = jbd2_journal_skip_recovery(journal);
1628
	if (write)
1629
		jbd2_journal_update_superblock(journal, 1);
1630 1631 1632 1633 1634 1635 1636 1637 1638

 no_recovery:
	return err;
}

/*
 * Journal abort has very specific semantics, which we describe
 * for journal abort.
 *
1639
 * Two internal functions, which provide abort to the jbd layer
1640 1641 1642 1643 1644 1645 1646 1647
 * itself are here.
 */

/*
 * Quick version for internal journal use (doesn't lock the journal).
 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
 * and don't attempt to make any other journal updates.
 */
1648
void __jbd2_journal_abort_hard(journal_t *journal)
1649 1650 1651
{
	transaction_t *transaction;

1652
	if (journal->j_flags & JBD2_ABORT)
1653 1654 1655
		return;

	printk(KERN_ERR "Aborting journal on device %s.\n",
1656
	       journal->j_devname);
1657 1658

	spin_lock(&journal->j_state_lock);
1659
	journal->j_flags |= JBD2_ABORT;
1660 1661
	transaction = journal->j_running_transaction;
	if (transaction)
1662
		__jbd2_log_start_commit(journal, transaction->t_tid);
1663 1664 1665 1666 1667 1668 1669
	spin_unlock(&journal->j_state_lock);
}

/* Soft abort: record the abort error status in the journal superblock,
 * but don't do any other IO. */
static void __journal_abort_soft (journal_t *journal, int errno)
{
1670
	if (journal->j_flags & JBD2_ABORT)
1671 1672 1673 1674 1675
		return;

	if (!journal->j_errno)
		journal->j_errno = errno;

1676
	__jbd2_journal_abort_hard(journal);
1677 1678

	if (errno)
1679
		jbd2_journal_update_superblock(journal, 1);
1680 1681 1682
}

/**
1683
 * void jbd2_journal_abort () - Shutdown the journal immediately.
1684 1685 1686 1687 1688 1689 1690 1691
 * @journal: the journal to shutdown.
 * @errno:   an error number to record in the journal indicating
 *           the reason for the shutdown.
 *
 * Perform a complete, immediate shutdown of the ENTIRE
 * journal (not of a single transaction).  This operation cannot be
 * undone without closing and reopening the journal.
 *
1692
 * The jbd2_journal_abort function is intended to support higher level error
1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707
 * recovery mechanisms such as the ext2/ext3 remount-readonly error
 * mode.
 *
 * Journal abort has very specific semantics.  Any existing dirty,
 * unjournaled buffers in the main filesystem will still be written to
 * disk by bdflush, but the journaling mechanism will be suspended
 * immediately and no further transaction commits will be honoured.
 *
 * Any dirty, journaled buffers will be written back to disk without
 * hitting the journal.  Atomicity cannot be guaranteed on an aborted
 * filesystem, but we _do_ attempt to leave as much data as possible
 * behind for fsck to use for cleanup.
 *
 * Any attempt to get a new transaction handle on a journal which is in
 * 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 1710 1711
 * entered abort state during the update.
 *
 * Recursive transactions are not disturbed by journal abort until the
1712
 * final jbd2_journal_stop, which will receive the -EIO error.
1713
 *
1714
 * Finally, the jbd2_journal_abort call allows the caller to supply an errno
1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727
 * which will be recorded (if possible) in the journal superblock.  This
 * allows a client to record failure conditions in the middle of a
 * transaction without having to complete the transaction to record the
 * failure to disk.  ext3_error, for example, now uses this
 * functionality.
 *
 * Errors which originate from within the journaling layer will NOT
 * supply an errno; a null errno implies that absolutely no further
 * writes are done to the journal (unless there are any already in
 * progress).
 *
 */

1728
void jbd2_journal_abort(journal_t *journal, int errno)
1729 1730 1731 1732 1733
{
	__journal_abort_soft(journal, errno);
}

/**
1734
 * int jbd2_journal_errno () - returns the journal's error state.
1735 1736
 * @journal: journal to examine.
 *
1737
 * This is the errno number set with jbd2_journal_abort(), the last
1738 1739 1740 1741 1742 1743
 * time the journal was mounted - if the journal was stopped
 * without calling abort this will be 0.
 *
 * If the journal has been aborted on this mount time -EROFS will
 * be returned.
 */
1744
int jbd2_journal_errno(journal_t *journal)
1745 1746 1747 1748
{
	int err;

	spin_lock(&journal->j_state_lock);
1749
	if (journal->j_flags & JBD2_ABORT)
1750 1751 1752 1753 1754 1755 1756 1757
		err = -EROFS;
	else
		err = journal->j_errno;
	spin_unlock(&journal->j_state_lock);
	return err;
}

/**
1758
 * int jbd2_journal_clear_err () - clears the journal's error state
1759 1760
 * @journal: journal to act on.
 *
1761
 * An error must be cleared or acked to take a FS out of readonly
1762 1763
 * mode.
 */
1764
int jbd2_journal_clear_err(journal_t *journal)
1765 1766 1767 1768
{
	int err = 0;

	spin_lock(&journal->j_state_lock);
1769
	if (journal->j_flags & JBD2_ABORT)
1770 1771 1772 1773 1774 1775 1776 1777
		err = -EROFS;
	else
		journal->j_errno = 0;
	spin_unlock(&journal->j_state_lock);
	return err;
}

/**
1778
 * void jbd2_journal_ack_err() - Ack journal err.
1779 1780
 * @journal: journal to act on.
 *
1781
 * An error must be cleared or acked to take a FS out of readonly
1782 1783
 * mode.
 */
1784
void jbd2_journal_ack_err(journal_t *journal)
1785 1786 1787
{
	spin_lock(&journal->j_state_lock);
	if (journal->j_errno)
1788
		journal->j_flags |= JBD2_ACK_ERR;
1789 1790 1791
	spin_unlock(&journal->j_state_lock);
}

1792
int jbd2_journal_blocks_per_page(struct inode *inode)
1793 1794 1795 1796
{
	return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
}

Z
Zach Brown 已提交
1797 1798 1799 1800 1801 1802
/*
 * helper functions to deal with 32 or 64bit block numbers.
 */
size_t journal_tag_bytes(journal_t *journal)
{
	if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
1803
		return JBD2_TAG_SIZE64;
Z
Zach Brown 已提交
1804
	else
1805
		return JBD2_TAG_SIZE32;
Z
Zach Brown 已提交
1806 1807
}

1808 1809 1810
/*
 * Journal_head storage management
 */
1811
static struct kmem_cache *jbd2_journal_head_cache;
1812
#ifdef CONFIG_JBD2_DEBUG
1813 1814 1815
static atomic_t nr_journal_heads = ATOMIC_INIT(0);
#endif

1816
static int journal_init_jbd2_journal_head_cache(void)
1817 1818 1819
{
	int retval;

A
Al Viro 已提交
1820
	J_ASSERT(jbd2_journal_head_cache == NULL);
J
Johann Lombardi 已提交
1821
	jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
1822 1823
				sizeof(struct journal_head),
				0,		/* offset */
1824
				SLAB_TEMPORARY,	/* flags */
1825
				NULL);		/* ctor */
1826
	retval = 0;
A
Al Viro 已提交
1827
	if (!jbd2_journal_head_cache) {
1828 1829 1830 1831 1832 1833
		retval = -ENOMEM;
		printk(KERN_EMERG "JBD: no memory for journal_head cache\n");
	}
	return retval;
}

1834
static void jbd2_journal_destroy_jbd2_journal_head_cache(void)
1835
{
1836 1837 1838 1839
	if (jbd2_journal_head_cache) {
		kmem_cache_destroy(jbd2_journal_head_cache);
		jbd2_journal_head_cache = NULL;
	}
1840 1841 1842 1843 1844 1845 1846 1847 1848 1849
}

/*
 * journal_head splicing and dicing
 */
static struct journal_head *journal_alloc_journal_head(void)
{
	struct journal_head *ret;
	static unsigned long last_warning;

1850
#ifdef CONFIG_JBD2_DEBUG
1851 1852
	atomic_inc(&nr_journal_heads);
#endif
1853
	ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS);
A
Al Viro 已提交
1854
	if (!ret) {
1855 1856 1857
		jbd_debug(1, "out of memory for journal_head\n");
		if (time_after(jiffies, last_warning + 5*HZ)) {
			printk(KERN_NOTICE "ENOMEM in %s, retrying.\n",
1858
			       __func__);
1859 1860
			last_warning = jiffies;
		}
A
Al Viro 已提交
1861
		while (!ret) {
1862
			yield();
1863
			ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS);
1864 1865 1866 1867 1868 1869 1870
		}
	}
	return ret;
}

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));
1874
#endif
1875
	kmem_cache_free(jbd2_journal_head_cache, jh);
1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893
}

/*
 * A journal_head is attached to a buffer_head whenever JBD has an
 * interest in the buffer.
 *
 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
 * is set.  This bit is tested in core kernel code where we need to take
 * JBD-specific actions.  Testing the zeroness of ->b_private is not reliable
 * there.
 *
 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
 *
 * When a buffer has its BH_JBD bit set it is immune from being released by
 * core kernel code, mainly via ->b_count.
 *
 * A journal_head may be detached from its buffer_head when the journal_head's
 * 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 1896 1897 1898
 * journal_head can be dropped if needed.
 *
 * Various places in the kernel want to attach a journal_head to a buffer_head
 * _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.
1902 1903 1904 1905
 *
 * So the typical usage would be:
 *
 *	(Attach a journal_head if needed.  Increments b_jcount)
1906
 *	struct journal_head *jh = jbd2_journal_add_journal_head(bh);
1907 1908
 *	...
 *	jh->b_transaction = xxx;
1909
 *	jbd2_journal_put_journal_head(jh);
1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920
 *
 * Now, the journal_head's b_jcount is zero, but it is safe from being released
 * because it has a non-zero b_transaction.
 */

/*
 * Give a buffer_head a journal_head.
 *
 * Doesn't need the journal lock.
 * May sleep.
 */
1921
struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963
{
	struct journal_head *jh;
	struct journal_head *new_jh = NULL;

repeat:
	if (!buffer_jbd(bh)) {
		new_jh = journal_alloc_journal_head();
		memset(new_jh, 0, sizeof(*new_jh));
	}

	jbd_lock_bh_journal_head(bh);
	if (buffer_jbd(bh)) {
		jh = bh2jh(bh);
	} else {
		J_ASSERT_BH(bh,
			(atomic_read(&bh->b_count) > 0) ||
			(bh->b_page && bh->b_page->mapping));

		if (!new_jh) {
			jbd_unlock_bh_journal_head(bh);
			goto repeat;
		}

		jh = new_jh;
		new_jh = NULL;		/* We consumed it */
		set_buffer_jbd(bh);
		bh->b_private = jh;
		jh->b_bh = bh;
		get_bh(bh);
		BUFFER_TRACE(bh, "added journal_head");
	}
	jh->b_jcount++;
	jbd_unlock_bh_journal_head(bh);
	if (new_jh)
		journal_free_journal_head(new_jh);
	return bh->b_private;
}

/*
 * Grab a ref against this buffer_head's journal_head.  If it ended up not
 * having a journal_head, return NULL
 */
1964
struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994
{
	struct journal_head *jh = NULL;

	jbd_lock_bh_journal_head(bh);
	if (buffer_jbd(bh)) {
		jh = bh2jh(bh);
		jh->b_jcount++;
	}
	jbd_unlock_bh_journal_head(bh);
	return jh;
}

static void __journal_remove_journal_head(struct buffer_head *bh)
{
	struct journal_head *jh = bh2jh(bh);

	J_ASSERT_JH(jh, jh->b_jcount >= 0);

	get_bh(bh);
	if (jh->b_jcount == 0) {
		if (jh->b_transaction == NULL &&
				jh->b_next_transaction == NULL &&
				jh->b_cp_transaction == NULL) {
			J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
			J_ASSERT_BH(bh, buffer_jbd(bh));
			J_ASSERT_BH(bh, jh2bh(jh) == bh);
			BUFFER_TRACE(bh, "remove journal_head");
			if (jh->b_frozen_data) {
				printk(KERN_WARNING "%s: freeing "
						"b_frozen_data\n",
1995
						__func__);
M
Mingming Cao 已提交
1996
				jbd2_free(jh->b_frozen_data, bh->b_size);
1997 1998 1999 2000
			}
			if (jh->b_committed_data) {
				printk(KERN_WARNING "%s: freeing "
						"b_committed_data\n",
2001
						__func__);
M
Mingming Cao 已提交
2002
				jbd2_free(jh->b_committed_data, bh->b_size);
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
			}
			bh->b_private = NULL;
			jh->b_bh = NULL;	/* debug, really */
			clear_buffer_jbd(bh);
			__brelse(bh);
			journal_free_journal_head(jh);
		} else {
			BUFFER_TRACE(bh, "journal_head was locked");
		}
	}
}

/*
2016
 * jbd2_journal_remove_journal_head(): if the buffer isn't attached to a transaction
2017 2018 2019 2020 2021 2022 2023
 * and has a zero b_jcount then remove and release its journal_head.   If we did
 * see that the buffer is not used by any transaction we also "logically"
 * decrement ->b_count.
 *
 * We in fact take an additional increment on ->b_count as a convenience,
 * because the caller usually wants to do additional things with the bh
 * after calling here.
2024
 * The caller of jbd2_journal_remove_journal_head() *must* run __brelse(bh) at some
2025 2026 2027
 * time.  Once the caller has run __brelse(), the buffer is eligible for
 * reaping by try_to_free_buffers().
 */
2028
void jbd2_journal_remove_journal_head(struct buffer_head *bh)
2029 2030 2031 2032 2033 2034 2035 2036 2037 2038
{
	jbd_lock_bh_journal_head(bh);
	__journal_remove_journal_head(bh);
	jbd_unlock_bh_journal_head(bh);
}

/*
 * Drop a reference on the passed journal_head.  If it fell to zero then try to
 * release the journal_head from the buffer_head.
 */
2039
void jbd2_journal_put_journal_head(struct journal_head *jh)
2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052
{
	struct buffer_head *bh = jh2bh(jh);

	jbd_lock_bh_journal_head(bh);
	J_ASSERT_JH(jh, jh->b_jcount > 0);
	--jh->b_jcount;
	if (!jh->b_jcount && !jh->b_transaction) {
		__journal_remove_journal_head(bh);
		__brelse(bh);
	}
	jbd_unlock_bh_journal_head(bh);
}

2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100
/*
 * Initialize jbd inode head
 */
void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
{
	jinode->i_transaction = NULL;
	jinode->i_next_transaction = NULL;
	jinode->i_vfs_inode = inode;
	jinode->i_flags = 0;
	INIT_LIST_HEAD(&jinode->i_list);
}

/*
 * Function to be called before we start removing inode from memory (i.e.,
 * clear_inode() is a fine place to be called from). It removes inode from
 * transaction's lists.
 */
void jbd2_journal_release_jbd_inode(journal_t *journal,
				    struct jbd2_inode *jinode)
{
	int writeout = 0;

	if (!journal)
		return;
restart:
	spin_lock(&journal->j_list_lock);
	/* Is commit writing out inode - we have to wait */
	if (jinode->i_flags & JI_COMMIT_RUNNING) {
		wait_queue_head_t *wq;
		DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
		wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
		prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
		spin_unlock(&journal->j_list_lock);
		schedule();
		finish_wait(wq, &wait.wait);
		goto restart;
	}

	/* Do we need to wait for data writeback? */
	if (journal->j_committing_transaction == jinode->i_transaction)
		writeout = 1;
	if (jinode->i_transaction) {
		list_del(&jinode->i_list);
		jinode->i_transaction = NULL;
	}
	spin_unlock(&journal->j_list_lock);
}

2101
/*
2102
 * debugfs tunables
2103
 */
J
Jose R. Santos 已提交
2104 2105
#ifdef CONFIG_JBD2_DEBUG
u8 jbd2_journal_enable_debug __read_mostly;
2106
EXPORT_SYMBOL(jbd2_journal_enable_debug);
2107

2108
#define JBD2_DEBUG_NAME "jbd2-debug"
2109

J
Jose R. Santos 已提交
2110 2111
static struct dentry *jbd2_debugfs_dir;
static struct dentry *jbd2_debug;
2112

2113 2114 2115 2116 2117 2118 2119
static void __init jbd2_create_debugfs_entry(void)
{
	jbd2_debugfs_dir = debugfs_create_dir("jbd2", NULL);
	if (jbd2_debugfs_dir)
		jbd2_debug = debugfs_create_u8(JBD2_DEBUG_NAME, S_IRUGO,
					       jbd2_debugfs_dir,
					       &jbd2_journal_enable_debug);
2120 2121
}

2122
static void __exit jbd2_remove_debugfs_entry(void)
2123
{
J
Jose R. Santos 已提交
2124 2125
	debugfs_remove(jbd2_debug);
	debugfs_remove(jbd2_debugfs_dir);
2126 2127
}

2128
#else
2129

2130
static void __init jbd2_create_debugfs_entry(void)
2131 2132 2133
{
}

2134
static void __exit jbd2_remove_debugfs_entry(void)
2135 2136 2137 2138 2139
{
}

#endif

2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161
#ifdef CONFIG_PROC_FS

#define JBD2_STATS_PROC_NAME "fs/jbd2"

static void __init jbd2_create_jbd_stats_proc_entry(void)
{
	proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
}

static void __exit jbd2_remove_jbd_stats_proc_entry(void)
{
	if (proc_jbd2_stats)
		remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
}

#else

#define jbd2_create_jbd_stats_proc_entry() do {} while (0)
#define jbd2_remove_jbd_stats_proc_entry() do {} while (0)

#endif

2162
struct kmem_cache *jbd2_handle_cache;
2163 2164 2165

static int __init journal_init_handle_cache(void)
{
J
Johann Lombardi 已提交
2166
	jbd2_handle_cache = kmem_cache_create("jbd2_journal_handle",
2167 2168
				sizeof(handle_t),
				0,		/* offset */
2169
				SLAB_TEMPORARY,	/* flags */
2170
				NULL);		/* ctor */
2171
	if (jbd2_handle_cache == NULL) {
2172 2173 2174 2175 2176 2177
		printk(KERN_EMERG "JBD: failed to create handle cache\n");
		return -ENOMEM;
	}
	return 0;
}

2178
static void jbd2_journal_destroy_handle_cache(void)
2179
{
2180 2181
	if (jbd2_handle_cache)
		kmem_cache_destroy(jbd2_handle_cache);
2182 2183 2184 2185 2186 2187 2188 2189 2190 2191
}

/*
 * Module startup and shutdown
 */

static int __init journal_init_caches(void)
{
	int ret;

2192
	ret = jbd2_journal_init_revoke_caches();
2193
	if (ret == 0)
2194
		ret = journal_init_jbd2_journal_head_cache();
2195 2196 2197 2198 2199
	if (ret == 0)
		ret = journal_init_handle_cache();
	return ret;
}

2200
static void jbd2_journal_destroy_caches(void)
2201
{
2202 2203 2204
	jbd2_journal_destroy_revoke_caches();
	jbd2_journal_destroy_jbd2_journal_head_cache();
	jbd2_journal_destroy_handle_cache();
2205 2206 2207 2208 2209 2210 2211 2212 2213
}

static int __init journal_init(void)
{
	int ret;

	BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);

	ret = journal_init_caches();
2214 2215 2216 2217
	if (ret == 0) {
		jbd2_create_debugfs_entry();
		jbd2_create_jbd_stats_proc_entry();
	} else {
2218
		jbd2_journal_destroy_caches();
2219
	}
2220 2221 2222 2223 2224
	return ret;
}

static void __exit journal_exit(void)
{
2225
#ifdef CONFIG_JBD2_DEBUG
2226 2227 2228 2229
	int n = atomic_read(&nr_journal_heads);
	if (n)
		printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n);
#endif
2230
	jbd2_remove_debugfs_entry();
2231
	jbd2_remove_jbd_stats_proc_entry();
2232
	jbd2_journal_destroy_caches();
2233 2234
}

2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263
/* 
 * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 
 * tracing infrastructure to map a dev_t to a device name.
 *
 * The caller should use rcu_read_lock() in order to make sure the
 * device name stays valid until its done with it.  We use
 * rcu_read_lock() as well to make sure we're safe in case the caller
 * gets sloppy, and because rcu_read_lock() is cheap and can be safely
 * nested.
 */
struct devname_cache {
	struct rcu_head	rcu;
	dev_t		device;
	char		devname[BDEVNAME_SIZE];
};
#define CACHE_SIZE_BITS 6
static struct devname_cache *devcache[1 << CACHE_SIZE_BITS];
static DEFINE_SPINLOCK(devname_cache_lock);

static void free_devcache(struct rcu_head *rcu)
{
	kfree(rcu);
}

const char *jbd2_dev_to_name(dev_t device)
{
	int	i = hash_32(device, CACHE_SIZE_BITS);
	char	*ret;
	struct block_device *bd;
2264
	static struct devname_cache *new_dev;
2265 2266 2267 2268 2269 2270 2271 2272 2273

	rcu_read_lock();
	if (devcache[i] && devcache[i]->device == device) {
		ret = devcache[i]->devname;
		rcu_read_unlock();
		return ret;
	}
	rcu_read_unlock();

2274 2275 2276
	new_dev = kmalloc(sizeof(struct devname_cache), GFP_KERNEL);
	if (!new_dev)
		return "NODEV-ALLOCFAILURE"; /* Something non-NULL */
2277 2278 2279
	spin_lock(&devname_cache_lock);
	if (devcache[i]) {
		if (devcache[i]->device == device) {
2280
			kfree(new_dev);
2281 2282 2283 2284 2285 2286
			ret = devcache[i]->devname;
			spin_unlock(&devname_cache_lock);
			return ret;
		}
		call_rcu(&devcache[i]->rcu, free_devcache);
	}
2287
	devcache[i] = new_dev;
2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300
	devcache[i]->device = device;
	bd = bdget(device);
	if (bd) {
		bdevname(bd, devcache[i]->devname);
		bdput(bd);
	} else
		__bdevname(device, devcache[i]->devname);
	ret = devcache[i]->devname;
	spin_unlock(&devname_cache_lock);
	return ret;
}
EXPORT_SYMBOL(jbd2_dev_to_name);

2301 2302 2303 2304
MODULE_LICENSE("GPL");
module_init(journal_init);
module_exit(journal_exit);