bcachefs: Improve "unable to allocate journal write" message

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/journal_io.c

@@ -2034,7 +2034,8 @@ CLOSURE_CALLBACK(bch2_journal_write)
 		struct printbuf buf = PRINTBUF;
 		buf.atomic++;
 
-		prt_printf(&buf, bch2_fmt(c, "Unable to allocate journal write: %s"),
+		prt_printf(&buf, bch2_fmt(c, "Unable to allocate journal write at seq %llu: %s"),
+					  le64_to_cpu(w->data->seq),
 					  bch2_err_str(ret));
 		__bch2_journal_debug_to_text(&buf, j);
 		spin_unlock(&j->lock);