journal.c

linux 内核源代码

	if (status < 0) {
		mlog_errno(status);
		goto done;
	}

	mlog(0, "calling journal_init_inode\n");
	journal = journal_init_inode(inode);
	if (journal == NULL) {
		mlog(ML_ERROR, "Linux journal layer error\n");
		status = -EIO;
		goto done;
	}

	status = journal_load(journal);
	if (status < 0) {
		mlog_errno(status);
		if (!igrab(inode))
			BUG();
		journal_destroy(journal);
		goto done;
	}

	ocfs2_clear_journal_error(osb->sb, journal, slot_num);

	/* wipe the journal */
	mlog(0, "flushing the journal.\n");
	journal_lock_updates(journal);
	status = journal_flush(journal);
	journal_unlock_updates(journal);
	if (status < 0)
		mlog_errno(status);

	/* This will mark the node clean */
	flags = le32_to_cpu(fe->id1.journal1.ij_flags);
	flags &= ~OCFS2_JOURNAL_DIRTY_FL;
	fe->id1.journal1.ij_flags = cpu_to_le32(flags);

	status = ocfs2_write_block(osb, bh, inode);
	if (status < 0)
		mlog_errno(status);

	if (!igrab(inode))
		BUG();

	journal_destroy(journal);

done:
	/* drop the lock on this nodes journal */
	if (got_lock)
		ocfs2_meta_unlock(inode, 1);

	if (inode)
		iput(inode);

	if (bh)
		brelse(bh);

	mlog_exit(status);
	return status;
}

/*
 * Do the most important parts of node recovery:
 *  - Replay it's journal
 *  - Stamp a clean local allocator file
 *  - Stamp a clean truncate log
 *  - Mark the node clean
 *
 * If this function completes without error, a node in OCFS2 can be
 * said to have been safely recovered. As a result, failure during the
 * second part of a nodes recovery process (local alloc recovery) is
 * far less concerning.
 */
static int ocfs2_recover_node(struct ocfs2_super *osb,
			      int node_num)
{
	int status = 0;
	int slot_num;
	struct ocfs2_slot_info *si = osb->slot_info;
	struct ocfs2_dinode *la_copy = NULL;
	struct ocfs2_dinode *tl_copy = NULL;

	mlog_entry("(node_num=%d, osb->node_num = %d)\n",
		   node_num, osb->node_num);

	mlog(0, "checking node %d\n", node_num);

	/* Should not ever be called to recover ourselves -- in that
	 * case we should've called ocfs2_journal_load instead. */
	BUG_ON(osb->node_num == node_num);

	slot_num = ocfs2_node_num_to_slot(si, node_num);
	if (slot_num == OCFS2_INVALID_SLOT) {
		status = 0;
		mlog(0, "no slot for this node, so no recovery required.\n");
		goto done;
	}

	mlog(0, "node %d was using slot %d\n", node_num, slot_num);

	status = ocfs2_replay_journal(osb, node_num, slot_num);
	if (status < 0) {
		mlog_errno(status);
		goto done;
	}

	/* Stamp a clean local alloc file AFTER recovering the journal... */
	status = ocfs2_begin_local_alloc_recovery(osb, slot_num, &la_copy);
	if (status < 0) {
		mlog_errno(status);
		goto done;
	}

	/* An error from begin_truncate_log_recovery is not
	 * serious enough to warrant halting the rest of
	 * recovery. */
	status = ocfs2_begin_truncate_log_recovery(osb, slot_num, &tl_copy);
	if (status < 0)
		mlog_errno(status);

	/* Likewise, this would be a strange but ultimately not so
	 * harmful place to get an error... */
	ocfs2_clear_slot(si, slot_num);
	status = ocfs2_update_disk_slots(osb, si);
	if (status < 0)
		mlog_errno(status);

	/* This will kfree the memory pointed to by la_copy and tl_copy */
	ocfs2_queue_recovery_completion(osb->journal, slot_num, la_copy,
					tl_copy);

	status = 0;
done:

	mlog_exit(status);
	return status;
}

/* Test node liveness by trylocking his journal. If we get the lock,
 * we drop it here. Return 0 if we got the lock, -EAGAIN if node is
 * still alive (we couldn't get the lock) and < 0 on error. */
static int ocfs2_trylock_journal(struct ocfs2_super *osb,
				 int slot_num)
{
	int status, flags;
	struct inode *inode = NULL;

	inode = ocfs2_get_system_file_inode(osb, JOURNAL_SYSTEM_INODE,
					    slot_num);
	if (inode == NULL) {
		mlog(ML_ERROR, "access error\n");
		status = -EACCES;
		goto bail;
	}
	if (is_bad_inode(inode)) {
		mlog(ML_ERROR, "access error (bad inode)\n");
		iput(inode);
		inode = NULL;
		status = -EACCES;
		goto bail;
	}
	SET_INODE_JOURNAL(inode);

	flags = OCFS2_META_LOCK_RECOVERY | OCFS2_META_LOCK_NOQUEUE;
	status = ocfs2_meta_lock_full(inode, NULL, 1, flags);
	if (status < 0) {
		if (status != -EAGAIN)
			mlog_errno(status);
		goto bail;
	}

	ocfs2_meta_unlock(inode, 1);
bail:
	if (inode)
		iput(inode);

	return status;
}

/* Call this underneath ocfs2_super_lock. It also assumes that the
 * slot info struct has been updated from disk. */
int ocfs2_mark_dead_nodes(struct ocfs2_super *osb)
{
	int status, i, node_num;
	struct ocfs2_slot_info *si = osb->slot_info;

	/* This is called with the super block cluster lock, so we
	 * know that the slot map can't change underneath us. */

	spin_lock(&si->si_lock);
	for(i = 0; i < si->si_num_slots; i++) {
		if (i == osb->slot_num)
			continue;
		if (ocfs2_is_empty_slot(si, i))
			continue;

		node_num = si->si_global_node_nums[i];
		if (ocfs2_node_map_test_bit(osb, &osb->recovery_map, node_num))
			continue;
		spin_unlock(&si->si_lock);

		/* Ok, we have a slot occupied by another node which
		 * is not in the recovery map. We trylock his journal
		 * file here to test if he's alive. */
		status = ocfs2_trylock_journal(osb, i);
		if (!status) {
			/* Since we're called from mount, we know that
			 * the recovery thread can't race us on
			 * setting / checking the recovery bits. */
			ocfs2_recovery_thread(osb, node_num);
		} else if ((status < 0) && (status != -EAGAIN)) {
			mlog_errno(status);
			goto bail;
		}

		spin_lock(&si->si_lock);
	}
	spin_unlock(&si->si_lock);

	status = 0;
bail:
	mlog_exit(status);
	return status;
}

struct ocfs2_orphan_filldir_priv {
	struct inode		*head;
	struct ocfs2_super	*osb;
};

static int ocfs2_orphan_filldir(void *priv, const char *name, int name_len,
				loff_t pos, u64 ino, unsigned type)
{
	struct ocfs2_orphan_filldir_priv *p = priv;
	struct inode *iter;

	if (name_len == 1 && !strncmp(".", name, 1))
		return 0;
	if (name_len == 2 && !strncmp("..", name, 2))
		return 0;

	/* Skip bad inodes so that recovery can continue */
	iter = ocfs2_iget(p->osb, ino,
			  OCFS2_FI_FLAG_ORPHAN_RECOVERY);
	if (IS_ERR(iter))
		return 0;

	mlog(0, "queue orphan %llu\n",
	     (unsigned long long)OCFS2_I(iter)->ip_blkno);
	/* No locking is required for the next_orphan queue as there
	 * is only ever a single process doing orphan recovery. */
	OCFS2_I(iter)->ip_next_orphan = p->head;
	p->head = iter;

	return 0;
}

static int ocfs2_queue_orphans(struct ocfs2_super *osb,
			       int slot,
			       struct inode **head)
{
	int status;
	struct inode *orphan_dir_inode = NULL;
	struct ocfs2_orphan_filldir_priv priv;
	loff_t pos = 0;

	priv.osb = osb;
	priv.head = *head;

	orphan_dir_inode = ocfs2_get_system_file_inode(osb,
						       ORPHAN_DIR_SYSTEM_INODE,
						       slot);
	if  (!orphan_dir_inode) {
		status = -ENOENT;
		mlog_errno(status);
		return status;
	}	

	mutex_lock(&orphan_dir_inode->i_mutex);
	status = ocfs2_meta_lock(orphan_dir_inode, NULL, 0);
	if (status < 0) {
		mlog_errno(status);
		goto out;
	}

	status = ocfs2_dir_foreach(orphan_dir_inode, &pos, &priv,
				   ocfs2_orphan_filldir);
	if (status) {
		mlog_errno(status);
		goto out_cluster;
	}

	*head = priv.head;

out_cluster:
	ocfs2_meta_unlock(orphan_dir_inode, 0);
out:
	mutex_unlock(&orphan_dir_inode->i_mutex);
	iput(orphan_dir_inode);
	return status;
}

static int ocfs2_orphan_recovery_can_continue(struct ocfs2_super *osb,
					      int slot)
{
	int ret;

	spin_lock(&osb->osb_lock);
	ret = !osb->osb_orphan_wipes[slot];
	spin_unlock(&osb->osb_lock);
	return ret;
}

static void ocfs2_mark_recovering_orphan_dir(struct ocfs2_super *osb,
					     int slot)
{
	spin_lock(&osb->osb_lock);
	/* Mark ourselves such that new processes in delete_inode()
	 * know to quit early. */
	ocfs2_node_map_set_bit(osb, &osb->osb_recovering_orphan_dirs, slot);
	while (osb->osb_orphan_wipes[slot]) {
		/* If any processes are already in the middle of an
		 * orphan wipe on this dir, then we need to wait for
		 * them. */
		spin_unlock(&osb->osb_lock);
		wait_event_interruptible(osb->osb_wipe_event,
					 ocfs2_orphan_recovery_can_continue(osb, slot));
		spin_lock(&osb->osb_lock);
	}
	spin_unlock(&osb->osb_lock);
}

static void ocfs2_clear_recovering_orphan_dir(struct ocfs2_super *osb,
					      int slot)
{
	ocfs2_node_map_clear_bit(osb, &osb->osb_recovering_orphan_dirs, slot);
}

/*
 * Orphan recovery. Each mounted node has it's own orphan dir which we
 * must run during recovery. Our strategy here is to build a list of
 * the inodes in the orphan dir and iget/iput them. The VFS does
 * (most) of the rest of the work.
 *
 * Orphan recovery can happen at any time, not just mount so we have a
 * couple of extra considerations.
 *
 * - We grab as many inodes as we can under the orphan dir lock -
 *   doing iget() outside the orphan dir risks getting a reference on
 *   an invalid inode.
 * - We must be sure not to deadlock with other processes on the
 *   system wanting to run delete_inode(). This can happen when they go
 *   to lock the orphan dir and the orphan recovery process attempts to
 *   iget() inside the orphan dir lock. This can be avoided by
 *   advertising our state to ocfs2_delete_inode().
 */
static int ocfs2_recover_orphans(struct ocfs2_super *osb,
				 int slot)
{
	int ret = 0;
	struct inode *inode = NULL;
	struct inode *iter;
	struct ocfs2_inode_info *oi;

	mlog(0, "Recover inodes from orphan dir in slot %d\n", slot);

	ocfs2_mark_recovering_orphan_dir(osb, slot);
	ret = ocfs2_queue_orphans(osb, slot, &inode);
	ocfs2_clear_recovering_orphan_dir(osb, slot);

	/* Error here should be noted, but we want to continue with as
	 * many queued inodes as we've got. */
	if (ret)
		mlog_errno(ret);

	while (inode) {
		oi = OCFS2_I(inode);
		mlog(0, "iput orphan %llu\n", (unsigned long long)oi->ip_blkno);

		iter = oi->ip_next_orphan;

		spin_lock(&oi->ip_lock);
		/* Delete voting may have set these on the assumption
		 * that the other node would wipe them successfully.
		 * If they are still in the node's orphan dir, we need
		 * to reset that state. */
		oi->ip_flags &= ~(OCFS2_INODE_DELETED|OCFS2_INODE_SKIP_DELETE);

		/* Set the proper information to get us going into
		 * ocfs2_delete_inode. */
		oi->ip_flags |= OCFS2_INODE_MAYBE_ORPHANED;
		spin_unlock(&oi->ip_lock);

		iput(inode);

		inode = iter;
	}

	return ret;
}

static int ocfs2_wait_on_mount(struct ocfs2_super *osb)
{
	/* This check is good because ocfs2 will wait on our recovery
	 * thread before changing it to something other than MOUNTED
	 * or DISABLED. */
	wait_event(osb->osb_mount_event,
		   atomic_read(&osb->vol_state) == VOLUME_MOUNTED ||
		   atomic_read(&osb->vol_state) == VOLUME_DISABLED);

	/* If there's an error on mount, then we may never get to the
	 * MOUNTED flag, but this is set right before
	 * dismount_volume() so we can trust it. */
	if (atomic_read(&osb->vol_state) == VOLUME_DISABLED) {
		mlog(0, "mount error, exiting!\n");
		return -EBUSY;
	}

	return 0;
}

static int ocfs2_commit_thread(void *arg)
{
	int status;
	struct ocfs2_super *osb = arg;
	struct ocfs2_journal *journal = osb->journal;

	/* we can trust j_num_trans here because _should_stop() is only set in
	 * shutdown and nobody other than ourselves should be able to start
	 * transactions.  committing on shutdown might take a few iterations
	 * as final transactions put deleted inodes on the list */
	while (!(kthread_should_stop() &&
		 atomic_read(&journal->j_num_trans) == 0)) {

		wait_event_interruptible(osb->checkpoint_event,
					 atomic_read(&journal->j_num_trans)
					 || kthread_should_stop());

		status = ocfs2_commit_cache(osb);
		if (status < 0)
			mlog_errno(status);

		if (kthread_should_stop() && atomic_read(&journal->j_num_trans)){
			mlog(ML_KTHREAD,
			     "commit_thread: %u transactions pending on "
			     "shutdown\n",
			     atomic_read(&journal->j_num_trans));
		}
	}

	return 0;
}

/* Look for a dirty journal without taking any cluster locks. Used for
 * hard readonly access to determine whether the file system journals
 * require recovery. */
int ocfs2_check_journals_nolocks(struct ocfs2_super *osb)
{
	int ret = 0;
	unsigned int slot;
	struct buffer_head *di_bh;
	struct ocfs2_dinode *di;
	struct inode *journal = NULL;

	for(slot = 0; slot < osb->max_slots; slot++) {
		journal = ocfs2_get_system_file_inode(osb,
						      JOURNAL_SYSTEM_INODE,
						      slot);
		if (!journal || is_bad_inode(journal)) {
			ret = -EACCES;
			mlog_errno(ret);
			goto out;
		}

		di_bh = NULL;
		ret = ocfs2_read_block(osb, OCFS2_I(journal)->ip_blkno, &di_bh,
				       0, journal);
		if (ret < 0) {
			mlog_errno(ret);
			goto out;
		}

		di = (struct ocfs2_dinode *) di_bh->b_data;

		if (le32_to_cpu(di->id1.journal1.ij_flags) &
		    OCFS2_JOURNAL_DIRTY_FL)
			ret = -EROFS;

		brelse(di_bh);
		if (ret)
			break;
	}

out:
	if (journal)
		iput(journal);

	return ret;
}