From mboxrd@z Thu Jan 1 00:00:00 1970 From: bugzilla-daemon@bugzilla.kernel.org Subject: [Bug 105121] lseek(SEEK_DATA) hangs for a long time for sparse files in the page cache Date: Mon, 28 Sep 2015 15:15:29 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit To: linux-ext4@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.136]:37076 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933554AbbI1PPf (ORCPT ); Mon, 28 Sep 2015 11:15:35 -0400 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7A35B2073F for ; Mon, 28 Sep 2015 15:15:30 +0000 (UTC) Received: from bugzilla2.web.kernel.org (bugzilla2.web.kernel.org [172.20.200.52]) by mail.kernel.org (Postfix) with ESMTP id AE6D92073D for ; Mon, 28 Sep 2015 15:15:29 +0000 (UTC) In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: https://bugzilla.kernel.org/show_bug.cgi?id=105121 --- Comment #3 from Theodore Tso --- This implies that grep is using lseek(SEEK_DATA) as an optimization when users use grep on sparse files. So I'm guessing this is a Thing, but I'm at a loss why people are interested in running grep on a sparse file (with or without blocks preallocated using fallocate). Can you enlighten me as to why people (or at least you and your colleague) find it useful to run grep on such files? Not that it matters since this is a pretty clear optimization we should add to ext4; I'm just curious what the use case is. Thanks!! -- You are receiving this mail because: You are watching the assignee of the bug.