From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from merlin.infradead.org ([205.233.59.134]:59128 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750959AbeA2TFF (ORCPT ); Mon, 29 Jan 2018 14:05:05 -0500 Subject: Re: [PATCH v6 1/2] Return bytes transferred for partial direct I/O To: Goldwyn Rodrigues , linux-fsdevel@vger.kernel.org Cc: linux-block@vger.kernel.org, linux-xfs@vger.kernel.org, axboe@kernel.dk, ak@linux.intel.com, Goldwyn Rodrigues References: <20180129145741.29486-1-rgoldwyn@suse.de> From: Randy Dunlap Message-ID: <98449f4d-8ab7-15e6-d3dd-f547d58177e4@infradead.org> Date: Mon, 29 Jan 2018 11:04:54 -0800 MIME-Version: 1.0 In-Reply-To: <20180129145741.29486-1-rgoldwyn@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 01/29/2018 06:57 AM, Goldwyn Rodrigues wrote: > From: Goldwyn Rodrigues > > diff --git a/Documentation/sysctl/fs.txt b/Documentation/sysctl/fs.txt > index 6c00c1e2743f..72e213d62511 100644 > --- a/Documentation/sysctl/fs.txt > +++ b/Documentation/sysctl/fs.txt > @@ -76,6 +77,19 @@ dcache isn't pruned yet. > > ============================================================== > > +dio_short_writes: > + > +In case Direct I/O encounters an transient error, it returns a transient > +the errorcode, even if it has performed part of the write. error code, > +This flag, if on (default), will return the number of bytes written > +so far, as the write(2) symantics are. However, some older applications semantics > +still consider a direct write as an error if all of the I/O > +submitted is not complete. ie write(file, count, buf) != count. I.e. > +This option can be disabled on systems in order to support > +existing applications which do not expect short writes. and if my system has a mix of older applications and new ones, will they all work just fine? thanks, -- ~Randy