From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Weimer Subject: Re: Does fsync() block read and write ops on the same file? Date: Fri, 11 Dec 2009 12:53:11 +0000 Message-ID: <824onxekp4.fsf@mid.bfk.de> References: <82ein3npyc.fsf@mid.bfk.de> <20091211035521.GI30608@discord.disaster> <82hbrxhoxa.fsf@mid.bfk.de> <20091211124224.GK30608@discord.disaster> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-fsdevel@vger.kernel.org To: Dave Chinner Return-path: Received: from mx01.bfk.de ([193.227.124.2]:50493 "EHLO mx01.bfk.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752837AbZLKMxH convert rfc822-to-8bit (ORCPT ); Fri, 11 Dec 2009 07:53:07 -0500 In-Reply-To: <20091211124224.GK30608@discord.disaster> (Dave Chinner's message of "Fri\, 11 Dec 2009 23\:42\:24 +1100") Sender: linux-fsdevel-owner@vger.kernel.org List-ID: * Dave Chinner: >> I'm not concerned with fsync latency per se. It's going to take a >> while to write a few GBs scattered across the file. However, it's >> annoying that read operations on the same file (which can't even see >> the effect of the fsync operation) are blocked, some times for more >> than two minutes. > > If they are blocking for that long then sysrq-w during that period > will tell us exactly where in what filesystem they are blocking on...= =2E Interesting. Is it possible to trigger this from the hang timer? =46rom that, I've got two traces: [307370.450502] Call Trace: [307370.450555] [] dput+0x1c/0xdd [307370.450590] [] __down_read+0x87/0xa1 [307370.450641] [] :xfs:xfs_ilock+0x31/0x60 [307370.450684] [] :xfs:xfs_read+0x147/0x21a [307370.450718] [] do_sync_read+0xc9/0x10c [307370.450750] [] autoremove_wake_function+0x0/0x2e [307370.450787] [] vfs_read+0xaa/0x152 [307370.450815] [] sys_read+0x45/0x6e [307370.450844] [] system_call_after_swapgs+0x8a/0x8= f [307396.186071] Call Trace: [307396.186128] [] __mutex_lock_slowpath+0x64/0x9b [307396.186160] [] mutex_lock+0xa/0xb [307396.186190] [] generic_file_llseek+0x2a/0x8b [307396.186219] [] sys_lseek+0x40/0x60 [307396.186248] [] system_call_after_swapgs+0x8a/0x8= f --=20 =46lorian Weimer BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstra=DFe 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html