示例#1
0
static
int
hammer_ioc_get_data(hammer_transaction_t trans, hammer_inode_t ip,
			struct hammer_ioc_data *data)
{
	struct hammer_cursor cursor;
	int bytes;
	int error;

	/* XXX cached inode ? */
	error = hammer_init_cursor(trans, &cursor, NULL, NULL);
	if (error)
		goto failed;

	cursor.key_beg = data->elm;
	cursor.flags |= HAMMER_CURSOR_BACKEND;

	error = hammer_btree_lookup(&cursor);
	if (error == 0) {
		error = hammer_btree_extract_data(&cursor);
		if (error == 0) {
			data->leaf = *cursor.leaf;
			bytes = cursor.leaf->data_len;
			if (bytes > data->size)
				bytes = data->size;
			error = copyout(cursor.data, data->ubuf, bytes);
		}
	}

failed:
	hammer_done_cursor(&cursor);
	return (error);
}
示例#2
0
/*
 * This works like write_rec but no write or update is necessary,
 * and no data payload is included so we couldn't do a write even
 * if we wanted to.
 *
 * We must still iterate for deletions, and we can validate the
 * record header which is a good way to test for corrupted mirror
 * targets XXX.
 *
 * mirror->key_cur must be carefully set when we succeed in processing
 * this mrec.
 */
static
int
hammer_ioc_mirror_write_pass(hammer_cursor_t cursor,
			     struct hammer_ioc_mrecord_rec *mrec,
			     struct hammer_ioc_mirror_rw *mirror,
			     u_int32_t localization)
{
	int error;

	/*
	 * Re-localize for target.  Relocalization of data is handled
	 * by hammer_mirror_write().
	 */
	mrec->leaf.base.localization &= HAMMER_LOCALIZE_MASK;
	mrec->leaf.base.localization += localization;

	/*
	 * Delete records through until we reach (non-inclusively) the
	 * target record.
	 */
	cursor->key_end = mrec->leaf.base;
	cursor->flags &= ~HAMMER_CURSOR_END_INCLUSIVE;
	cursor->flags |= HAMMER_CURSOR_BACKEND;
	error = hammer_mirror_delete_to(cursor, mirror);

	/*
	 * Certain records are not part of the mirroring operation
	 */
	if (hammer_mirror_nomirror(&mrec->leaf.base))
		return(0);

	/*
	 * Locate the record and get past it by setting ATEDISK.  Perform
	 * any necessary deletions.  We have no data payload and cannot
	 * create a new record.
	 */
	if (error == 0) {
		mirror->key_cur = mrec->leaf.base;
		cursor->key_beg = mrec->leaf.base;
		cursor->flags |= HAMMER_CURSOR_BACKEND;
		cursor->flags &= ~HAMMER_CURSOR_INSERT;
		error = hammer_btree_lookup(cursor);
		if (error == 0) {
			if (hammer_mirror_check(cursor, mrec))
				error = hammer_mirror_update(cursor, mrec);
			cursor->flags |= HAMMER_CURSOR_ATEDISK;
		} else {
			cursor->flags &= ~HAMMER_CURSOR_ATEDISK;
		}
		if (error == ENOENT)
			error = 0;
	}
	return(error);
}
示例#3
0
/*
 * Handle skip records.
 *
 * We must iterate from the last resolved record position at mirror->key_cur
 * to skip_beg non-inclusive and delete any records encountered.
 *
 * mirror->key_cur must be carefully set when we succeed in processing
 * this mrec.
 */
static int
hammer_ioc_mirror_write_skip(hammer_cursor_t cursor,
			     struct hammer_ioc_mrecord_skip *mrec,
			     struct hammer_ioc_mirror_rw *mirror,
			     u_int32_t localization)
{
	int error;

	/*
	 * Relocalize the skip range
	 */
	mrec->skip_beg.localization &= HAMMER_LOCALIZE_MASK;
	mrec->skip_beg.localization += localization;
	mrec->skip_end.localization &= HAMMER_LOCALIZE_MASK;
	mrec->skip_end.localization += localization;

	/*
	 * Iterate from current position to skip_beg, deleting any records
	 * we encounter.  The record at skip_beg is not included (it is
	 * skipped).
	 */
	cursor->key_end = mrec->skip_beg;
	cursor->flags &= ~HAMMER_CURSOR_END_INCLUSIVE;
	cursor->flags |= HAMMER_CURSOR_BACKEND;
	error = hammer_mirror_delete_to(cursor, mirror);

	/*
	 * Now skip past the skip (which is the whole point point of
	 * having a skip record).  The sender has not sent us any records
	 * for the skip area so we wouldn't know what to keep and what
	 * to delete anyway.
	 *
	 * Clear ATEDISK because skip_end is non-inclusive, so we can't
	 * count an exact match if we happened to get one.
	 */
	if (error == 0) {
		mirror->key_cur = mrec->skip_end;
		cursor->key_beg = mrec->skip_end;
		error = hammer_btree_lookup(cursor);
		cursor->flags &= ~HAMMER_CURSOR_ATEDISK;
		if (error == ENOENT)
			error = 0;
	}
	return(error);
}
示例#4
0
/*
 * Retrieve the PFS hammer cleanup utility config record.  This is
 * different (newer than) the PFS config.
 */
static
int
hammer_ioc_get_config(hammer_transaction_t trans, hammer_inode_t ip,
			struct hammer_ioc_config *config)
{
	struct hammer_cursor cursor;
	int error;

	error = hammer_init_cursor(trans, &cursor, &ip->cache[0], NULL);
	if (error) {
		hammer_done_cursor(&cursor);
		return(error);
	}

	cursor.key_beg.obj_id = HAMMER_OBJID_ROOT;
	cursor.key_beg.create_tid = 0;
	cursor.key_beg.delete_tid = 0;
	cursor.key_beg.obj_type = 0;
	cursor.key_beg.rec_type = HAMMER_RECTYPE_CONFIG;
	cursor.key_beg.localization = ip->obj_localization | HAMMER_LOCALIZE_INODE;
	cursor.key_beg.key = 0;		/* config space page 0 */

	cursor.asof = HAMMER_MAX_TID;
	cursor.flags |= HAMMER_CURSOR_ASOF;

	error = hammer_btree_lookup(&cursor);
	if (error == 0) {
		error = hammer_btree_extract_data(&cursor);
		if (error == 0)
			config->config = cursor.data->config;
	}
	/* error can be ENOENT */
	config->head.error = error;
	hammer_done_cursor(&cursor);
	return(0);
}
示例#5
0
/*
 * Write out a new record.
 */
static
int
hammer_mirror_write(hammer_cursor_t cursor,
		    struct hammer_ioc_mrecord_rec *mrec,
		    char *udata)
{
	hammer_transaction_t trans;
	hammer_buffer_t data_buffer;
	hammer_off_t ndata_offset;
	hammer_tid_t high_tid;
	void *ndata;
	int error;
	int doprop;

	trans = cursor->trans;
	data_buffer = NULL;

	/*
	 * Get the sync lock so the whole mess is atomic
	 */
	hammer_sync_lock_sh(trans);

	/*
	 * Allocate and adjust data
	 */
	if (mrec->leaf.data_len && mrec->leaf.data_offset) {
		ndata = hammer_alloc_data(trans, mrec->leaf.data_len,
					  mrec->leaf.base.rec_type,
					  &ndata_offset, &data_buffer,
					  0, &error);
		if (ndata == NULL)
			return(error);
		mrec->leaf.data_offset = ndata_offset;
		hammer_modify_buffer(trans, data_buffer, NULL, 0);
		error = copyin(udata, ndata, mrec->leaf.data_len);
		if (error == 0) {
			if (hammer_crc_test_leaf(ndata, &mrec->leaf) == 0) {
				kprintf("data crc mismatch on pipe\n");
				error = EINVAL;
			} else {
				error = hammer_mirror_localize_data(
							ndata, &mrec->leaf);
			}
		}
		hammer_modify_buffer_done(data_buffer);
	} else {
		mrec->leaf.data_offset = 0;
		error = 0;
		ndata = NULL;
	}
	if (error)
		goto failed;

	/*
	 * Do the insertion.  This can fail with a EDEADLK or EALREADY
	 */
	cursor->flags |= HAMMER_CURSOR_INSERT;
	error = hammer_btree_lookup(cursor);
	if (error != ENOENT) {
		if (error == 0)
			error = EALREADY;
		goto failed;
	}

	error = hammer_btree_insert(cursor, &mrec->leaf, &doprop);

	/*
	 * Cursor is left on the current element, we want to skip it now.
	 */
	cursor->flags |= HAMMER_CURSOR_ATEDISK;
	cursor->flags &= ~HAMMER_CURSOR_INSERT;

	/*
	 * Track a count of active inodes.
	 */
	if (error == 0 &&
	    mrec->leaf.base.rec_type == HAMMER_RECTYPE_INODE &&
	    mrec->leaf.base.delete_tid == 0) {
		hammer_modify_volume_field(trans,
					   trans->rootvol,
					   vol0_stat_inodes);
		++trans->hmp->rootvol->ondisk->vol0_stat_inodes;
		hammer_modify_volume_done(trans->rootvol);
	}

	/*
	 * vol0_next_tid must track the highest TID stored in the filesystem.
	 * We do not need to generate undo for this update.
	 */
	high_tid = mrec->leaf.base.create_tid;
	if (high_tid < mrec->leaf.base.delete_tid)
		high_tid = mrec->leaf.base.delete_tid;
	if (trans->rootvol->ondisk->vol0_next_tid < high_tid) {
		hammer_modify_volume(trans, trans->rootvol, NULL, 0);
		trans->rootvol->ondisk->vol0_next_tid = high_tid;
		hammer_modify_volume_done(trans->rootvol);
	}

	/*
	 * WARNING!  cursor's leaf pointer may have changed after
	 *	     do_propagation returns.
	 */
	if (error == 0 && doprop)
		hammer_btree_do_propagation(cursor, NULL, &mrec->leaf);

failed:
	/*
	 * Cleanup
	 */
	if (error && mrec->leaf.data_offset) {
		hammer_blockmap_free(cursor->trans,
				     mrec->leaf.data_offset,
				     mrec->leaf.data_len);
	}
	hammer_sync_unlock(trans);
	if (data_buffer)
		hammer_rel_buffer(data_buffer, 0);
	return(error);
}
示例#6
0
/*
 * Handle B-Tree records.
 *
 * We must iterate to mrec->base.key (non-inclusively), and then process
 * the record.  We are allowed to write a new record or delete an existing
 * record, but cannot replace an existing record.
 *
 * mirror->key_cur must be carefully set when we succeed in processing
 * this mrec.
 */
static int
hammer_ioc_mirror_write_rec(hammer_cursor_t cursor,
			    struct hammer_ioc_mrecord_rec *mrec,
			    struct hammer_ioc_mirror_rw *mirror,
			    u_int32_t localization,
			    char *uptr)
{
	int error;

	if (mrec->leaf.data_len < 0 || 
	    mrec->leaf.data_len > HAMMER_XBUFSIZE ||
	    mrec->leaf.data_len + sizeof(*mrec) > mrec->head.rec_size) {
		return(EINVAL);
	}

	/*
	 * Re-localize for target.  relocalization of data is handled
	 * by hammer_mirror_write().
	 */
	mrec->leaf.base.localization &= HAMMER_LOCALIZE_MASK;
	mrec->leaf.base.localization += localization;

	/*
	 * Delete records through until we reach (non-inclusively) the
	 * target record.
	 */
	cursor->key_end = mrec->leaf.base;
	cursor->flags &= ~HAMMER_CURSOR_END_INCLUSIVE;
	cursor->flags |= HAMMER_CURSOR_BACKEND;
	error = hammer_mirror_delete_to(cursor, mirror);

	/*
	 * Certain records are not part of the mirroring operation
	 */
	if (error == 0 && hammer_mirror_nomirror(&mrec->leaf.base))
		return(0);

	/*
	 * Locate the record.
	 *
	 * If the record exists only the delete_tid may be updated.
	 *
	 * If the record does not exist we can create it only if the
	 * create_tid is not too old.  If the create_tid is too old
	 * it may have already been destroyed on the slave from pruning.
	 *
	 * Note that mirror operations are effectively as-of operations
	 * and delete_tid can be 0 for mirroring purposes even if it is
	 * not actually 0 at the originator.
	 *
	 * These functions can return EDEADLK
	 */
	if (error == 0) {
		cursor->key_beg = mrec->leaf.base;
		cursor->flags |= HAMMER_CURSOR_BACKEND;
		cursor->flags &= ~HAMMER_CURSOR_INSERT;
		error = hammer_btree_lookup(cursor);
	}

	if (error == 0 && hammer_mirror_check(cursor, mrec)) {
		error = hammer_mirror_update(cursor, mrec);
	} else if (error == ENOENT) {
		if (mrec->leaf.base.create_tid >= mirror->tid_beg) {
			error = hammer_create_at_cursor(
					cursor, &mrec->leaf,
					uptr, HAMMER_CREATE_MODE_UMIRROR);
		} else {
			error = 0;
		}
	}
	if (error == 0 || error == EALREADY)
		mirror->key_cur = mrec->leaf.base;
	return(error);
}
示例#7
0
/*
 * Retrieve the PFS hammer cleanup utility config record.  This is
 * different (newer than) the PFS config.
 *
 * This is kinda a hack.
 */
static
int
hammer_ioc_set_config(hammer_transaction_t trans, hammer_inode_t ip,
			struct hammer_ioc_config *config)
{
	struct hammer_btree_leaf_elm leaf;
	struct hammer_cursor cursor;
	hammer_mount_t hmp = ip->hmp;
	int error;

again:
	error = hammer_init_cursor(trans, &cursor, &ip->cache[0], NULL);
	if (error) {
		hammer_done_cursor(&cursor);
		return(error);
	}

	bzero(&leaf, sizeof(leaf));
	leaf.base.obj_id = HAMMER_OBJID_ROOT;
	leaf.base.rec_type = HAMMER_RECTYPE_CONFIG;
	leaf.base.create_tid = hammer_alloc_tid(hmp, 1);
	leaf.base.btype = HAMMER_BTREE_TYPE_RECORD;
	leaf.base.localization = ip->obj_localization | HAMMER_LOCALIZE_INODE;
	leaf.base.key = 0;	/* page 0 */
	leaf.data_len = sizeof(struct hammer_config_data);

	cursor.key_beg = leaf.base;

	cursor.asof = HAMMER_MAX_TID;
	cursor.flags |= HAMMER_CURSOR_BACKEND | HAMMER_CURSOR_ASOF;

	error = hammer_btree_lookup(&cursor);
	if (error == 0) {
		error = hammer_btree_extract_data(&cursor);
		error = hammer_delete_at_cursor(&cursor, HAMMER_DELETE_DESTROY,
						0, 0, 0, NULL);
		if (error == EDEADLK) {
			hammer_done_cursor(&cursor);
			goto again;
		}
	}
	if (error == ENOENT)
		error = 0;
	if (error == 0) {
		/*
		 * NOTE: Must reload key_beg after an ASOF search because
		 *	 the create_tid may have been modified during the
		 *	 search.
		 */
		cursor.flags &= ~HAMMER_CURSOR_ASOF;
		cursor.key_beg = leaf.base;
		error = hammer_create_at_cursor(&cursor, &leaf,
						&config->config,
						HAMMER_CREATE_MODE_SYS);
		if (error == EDEADLK) {
			hammer_done_cursor(&cursor);
			goto again;
		}
	}
	config->head.error = error;
	hammer_done_cursor(&cursor);
	return(0);
}
示例#8
0
/*
 * Delete snapshot transaction id(s) from the list of snapshots.
 */
static
int
hammer_ioc_del_snapshot(hammer_transaction_t trans, hammer_inode_t ip,
			struct hammer_ioc_snapshot *snap)
{
	hammer_mount_t hmp = ip->hmp;
	struct hammer_cursor cursor;
	int error;

	/*
	 * Validate structure
	 */
	if (snap->count > HAMMER_SNAPS_PER_IOCTL)
		return (EINVAL);
	if (snap->index >= snap->count)
		return (EINVAL);

	hammer_lock_ex(&hmp->snapshot_lock);
again:
	/*
	 * Look for keys starting after the previous iteration, or at
	 * the beginning if snap->count is 0.
	 */
	error = hammer_init_cursor(trans, &cursor, &ip->cache[0], NULL);
	if (error) {
		hammer_done_cursor(&cursor);
		return(error);
	}

	cursor.key_beg.obj_id = HAMMER_OBJID_ROOT;
	cursor.key_beg.create_tid = 0;
	cursor.key_beg.delete_tid = 0;
	cursor.key_beg.obj_type = 0;
	cursor.key_beg.rec_type = HAMMER_RECTYPE_SNAPSHOT;
	cursor.key_beg.localization = ip->obj_localization | HAMMER_LOCALIZE_INODE;
	cursor.asof = HAMMER_MAX_TID;
	cursor.flags |= HAMMER_CURSOR_ASOF;

	while (snap->index < snap->count) {
		cursor.key_beg.key = (int64_t)snap->snaps[snap->index].tid;
		error = hammer_btree_lookup(&cursor);
		if (error)
			break;
		error = hammer_btree_extract_leaf(&cursor);
		if (error)
			break;
		error = hammer_delete_at_cursor(&cursor, HAMMER_DELETE_DESTROY,
						0, 0, 0, NULL);
		if (error == EDEADLK) {
			hammer_done_cursor(&cursor);
			goto again;
		}
		if (error)
			break;
		++snap->index;
	}
	snap->head.error = error;
	hammer_done_cursor(&cursor);
	hammer_unlock(&hmp->snapshot_lock);
	return(0);
}
示例#9
0
/*
 * Add a snapshot transaction id(s) to the list of snapshots.
 *
 * NOTE: Records are created with an allocated TID.  If a flush cycle
 *	 is in progress the record may be synced in the current flush
 *	 cycle and the volume header will reflect the allocation of the
 *	 TID, but the synchronization point may not catch up to the
 *	 TID until the next flush cycle.
 */
static
int
hammer_ioc_add_snapshot(hammer_transaction_t trans, hammer_inode_t ip,
			struct hammer_ioc_snapshot *snap)
{
	hammer_mount_t hmp = ip->hmp;
	struct hammer_btree_leaf_elm leaf;
	struct hammer_cursor cursor;
	int error;

	/*
	 * Validate structure
	 */
	if (snap->count > HAMMER_SNAPS_PER_IOCTL)
		return (EINVAL);
	if (snap->index >= snap->count)
		return (EINVAL);

	hammer_lock_ex(&hmp->snapshot_lock);
again:
	/*
	 * Look for keys starting after the previous iteration, or at
	 * the beginning if snap->count is 0.
	 */
	error = hammer_init_cursor(trans, &cursor, &ip->cache[0], NULL);
	if (error) {
		hammer_done_cursor(&cursor);
		return(error);
	}

	cursor.asof = HAMMER_MAX_TID;
	cursor.flags |= HAMMER_CURSOR_BACKEND | HAMMER_CURSOR_ASOF;

	bzero(&leaf, sizeof(leaf));
	leaf.base.obj_id = HAMMER_OBJID_ROOT;
	leaf.base.rec_type = HAMMER_RECTYPE_SNAPSHOT;
	leaf.base.create_tid = hammer_alloc_tid(hmp, 1);
	leaf.base.btype = HAMMER_BTREE_TYPE_RECORD;
	leaf.base.localization = ip->obj_localization | HAMMER_LOCALIZE_INODE;
	leaf.data_len = sizeof(struct hammer_snapshot_data);

	while (snap->index < snap->count) {
		leaf.base.key = (int64_t)snap->snaps[snap->index].tid;
		cursor.key_beg = leaf.base;
		error = hammer_btree_lookup(&cursor);
		if (error == 0) {
			error = EEXIST;
			break;
		}

		/*
		 * NOTE: Must reload key_beg after an ASOF search because
		 *	 the create_tid may have been modified during the
		 *	 search.
		 */
		cursor.flags &= ~HAMMER_CURSOR_ASOF;
		cursor.key_beg = leaf.base;
		error = hammer_create_at_cursor(&cursor, &leaf,
						&snap->snaps[snap->index],
						HAMMER_CREATE_MODE_SYS);
		if (error == EDEADLK) {
			hammer_done_cursor(&cursor);
			goto again;
		}
		cursor.flags |= HAMMER_CURSOR_ASOF;
		if (error)
			break;
		++snap->index;
	}
	snap->head.error = error;
	hammer_done_cursor(&cursor);
	hammer_unlock(&hmp->snapshot_lock);
	return(0);
}
示例#10
0
int
hammer_ioc_dedup(hammer_transaction_t trans, hammer_inode_t ip,
		 struct hammer_ioc_dedup *dedup)
{
	struct hammer_cursor cursor1, cursor2;
	int error;
	int seq;

	/*
	 * Enforce hammer filesystem version requirements
	 */
	if (trans->hmp->version < HAMMER_VOL_VERSION_FIVE) {
		kprintf("hammer: Filesystem must be upgraded to v5 "
			"before you can run dedup\n");
		return (EOPNOTSUPP); /* 95*/
	}

	/*
	 * Cursor1, return an error -> candidate goes to pass2 list
	 */
	error = hammer_init_cursor(trans, &cursor1, NULL, NULL);
	if (error)
		goto done_cursor;
	cursor1.key_beg = dedup->elm1;
	cursor1.flags |= HAMMER_CURSOR_BACKEND;

	error = hammer_btree_lookup(&cursor1);
	if (error)
		goto done_cursor;
	error = hammer_btree_extract(&cursor1, HAMMER_CURSOR_GET_LEAF |
						HAMMER_CURSOR_GET_DATA);
	if (error)
		goto done_cursor;

	/*
	 * Cursor2, return an error -> candidate goes to pass2 list
	 */
	error = hammer_init_cursor(trans, &cursor2, NULL, NULL);
	if (error)
		goto done_cursors;
	cursor2.key_beg = dedup->elm2;
	cursor2.flags |= HAMMER_CURSOR_BACKEND;

	error = hammer_btree_lookup(&cursor2);
	if (error)
		goto done_cursors;
	error = hammer_btree_extract(&cursor2, HAMMER_CURSOR_GET_LEAF |
						HAMMER_CURSOR_GET_DATA);
	if (error)
		goto done_cursors;

	/*
	 * Zone validation. We can't de-dup any of the other zones
	 * (BTREE or META) or bad things will happen.
	 *
	 * Return with error = 0, but set an INVALID_ZONE flag.
	 */
	error = validate_zone(cursor1.leaf->data_offset) +
			    validate_zone(cursor2.leaf->data_offset);
	if (error) {
		dedup->head.flags |= HAMMER_IOC_DEDUP_INVALID_ZONE;
		error = 0;
		goto done_cursors;
	}

	/*
	 * Comparison checks
	 *
	 * If zones don't match or data_len fields aren't the same
	 * we consider it to be a comparison failure.
	 *
	 * Return with error = 0, but set a CMP_FAILURE flag.
	 */
	if ((cursor1.leaf->data_offset & HAMMER_OFF_ZONE_MASK) !=
	    (cursor2.leaf->data_offset & HAMMER_OFF_ZONE_MASK)) {
		dedup->head.flags |= HAMMER_IOC_DEDUP_CMP_FAILURE;
		goto done_cursors;
	}
	if (cursor1.leaf->data_len != cursor2.leaf->data_len) {
		dedup->head.flags |= HAMMER_IOC_DEDUP_CMP_FAILURE;
		goto done_cursors;
	}

	/* byte-by-byte comparison to be sure */
	if (bcmp(cursor1.data, cursor2.data, cursor1.leaf->data_len)) {
		dedup->head.flags |= HAMMER_IOC_DEDUP_CMP_FAILURE;
		goto done_cursors;
	}

	/*
	 * Upgrade both cursors together to an exclusive lock
	 *
	 * Return an error -> candidate goes to pass2 list
	 */
	hammer_sync_lock_sh(trans);
	error = hammer_cursor_upgrade2(&cursor1, &cursor2);
	if (error) {
		hammer_sync_unlock(trans);
		goto done_cursors;
	}

	error = hammer_blockmap_dedup(cursor1.trans,
			cursor1.leaf->data_offset, cursor1.leaf->data_len);
	if (error) {
		if (error == ERANGE) {
			/*
			 * Return with error = 0, but set an UNDERFLOW flag
			 */
			dedup->head.flags |= HAMMER_IOC_DEDUP_UNDERFLOW;
			error = 0;
			goto downgrade_cursors;
		} else {
			/*
			 * Return an error -> block goes to pass2 list
			 */
			goto downgrade_cursors;
		}
	}

	/*
	 * The cursor2's cache must be invalidated before calling
	 * hammer_blockmap_free(), otherwise it will not be able to
	 * invalidate the underlying data buffer.
	 */
	hammer_cursor_invalidate_cache(&cursor2);
	hammer_blockmap_free(cursor2.trans,
			cursor2.leaf->data_offset, cursor2.leaf->data_len);

	hammer_modify_node(cursor2.trans, cursor2.node,
			&cursor2.leaf->data_offset, sizeof(hammer_off_t));
	cursor2.leaf->data_offset = cursor1.leaf->data_offset;
	hammer_modify_node_done(cursor2.node);

downgrade_cursors:
	hammer_cursor_downgrade2(&cursor1, &cursor2);
	hammer_sync_unlock(trans);
done_cursors:
	hammer_done_cursor(&cursor2);
done_cursor:
	hammer_done_cursor(&cursor1);

	/*
	 * Avoid deadlocking the buffer cache
	 */
	seq = trans->hmp->flusher.done;
	while (hammer_flusher_meta_halflimit(trans->hmp) ||
	       hammer_flusher_undo_exhausted(trans, 2)) {
		hammer_flusher_wait(trans->hmp, seq);
		seq = hammer_flusher_async_one(trans->hmp);
	}
	return (error);
}