xfs: better log intent item refcount checking

Use ASSERTs on the log intent item refcounts so that we fail noisily if
anyone tries to double-free the item.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/xfs_extfree_item.c

@@ -290,6 +290,7 @@ void
 xfs_efi_release(
 	struct xfs_efi_log_item	*efip)
 {
+	ASSERT(atomic_read(&efip->efi_refcount) > 0);
 	if (atomic_dec_and_test(&efip->efi_refcount)) {
 		xfs_trans_ail_remove(&efip->efi_item, SHUTDOWN_LOG_IO_ERROR);
 		xfs_efi_item_free(efip);