From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f70.google.com (mail-wm0-f70.google.com [74.125.82.70]) by kanga.kvack.org (Postfix) with ESMTP id C678D6B0393 for ; Tue, 28 Feb 2017 05:12:18 -0500 (EST) Received: by mail-wm0-f70.google.com with SMTP id c143so3913201wmd.2 for ; Tue, 28 Feb 2017 02:12:18 -0800 (PST) Received: from mail-wm0-x242.google.com (mail-wm0-x242.google.com. [2a00:1450:400c:c09::242]) by mx.google.com with ESMTPS id r186si2245869wmd.5.2017.02.28.02.12.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 Feb 2017 02:12:17 -0800 (PST) Received: by mail-wm0-x242.google.com with SMTP id m70so1533568wma.1 for ; Tue, 28 Feb 2017 02:12:17 -0800 (PST) Subject: Re: [Lsf-pc] [LSF/MM TOPIC] do we really need PG_error at all? References: <1488120164.2948.4.camel@redhat.com> <1488129033.4157.8.camel@HansenPartnership.com> <877f4cr7ew.fsf@notabene.neil.brown.name> <1488151856.4157.50.camel@HansenPartnership.com> <874lzgqy06.fsf@notabene.neil.brown.name> <1488208047.2876.6.camel@redhat.com> <87varvp5v1.fsf@notabene.neil.brown.name> <1488244308.7627.5.camel@redhat.com> From: Boaz Harrosh Message-ID: <0bea2b1c-ddb1-f2bf-8ef7-b83d6a6404fc@gmail.com> Date: Tue, 28 Feb 2017 12:12:14 +0200 MIME-Version: 1.0 In-Reply-To: <1488244308.7627.5.camel@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Jeff Layton , NeilBrown , Andreas Dilger Cc: linux-block@vger.kernel.org, linux-scsi , lsf-pc , Neil Brown , LKML , James Bottomley , linux-mm , linux-fsdevel On 02/28/2017 03:11 AM, Jeff Layton wrote: <> > > I'll probably have questions about the read side as well, but for now it > looks like it's mostly used in an ad-hoc way to communicate errors > across subsystems (block to fs layer, for instance). If memory does not fail me it used to be checked long time ago in the read-ahead case. On the buffered read case, the first page is read synchronous and any error is returned to the caller, but then a read-ahead chunk is read async all the while the original thread returned to the application. So any errors are only recorded on the page-bit, since otherwise the uptodate is off and the IO will be retransmitted. Then the move to read_iter changed all that I think. But again this is like 5-6 years ago, and maybe I didn't even understand very well. > -- > Jeff Layton > I would like a Documentation of all this as well please. Where are the tests for this? Thanks Boaz -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org