From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:48733 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753517AbdDDKyJ (ORCPT ); Tue, 4 Apr 2017 06:54:09 -0400 Subject: Re: [PATCH] btrfs: delete unused member nobarriers To: dsterba@suse.cz References: <20170331112608.32478-1-anand.jain@oracle.com> <20170403120639.GS4781@twin.jikos.cz> From: Anand Jain Cc: linux-btrfs@vger.kernel.org Message-ID: <735d9ef3-c3f2-2a2d-af7e-b65a8980e423@oracle.com> Date: Tue, 4 Apr 2017 18:59:19 +0800 MIME-Version: 1.0 In-Reply-To: <20170403120639.GS4781@twin.jikos.cz> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 04/03/2017 08:06 PM, David Sterba wrote: > Please update the changelog to say why it's ok to remove it, eg. the > commit that removed the last user. > > commit b25de9d6da49b1a8760a89672283128aa8c78345 > Author: Christoph Hellwig > Date: Fri Apr 24 21:41:01 2015 +0200 > > block: remove BIO_EOPNOTSUPP Ah. I should have search the commit log. sorry about that. IMO, there is a bug in generic_make_request_checks() in which it should rather return EOPNOTSUPP, instead of EIO if QUEUE_FLAG_WC is not supported. ------------------------------------------------ 1853 static noinline_for_stack bool 1854 generic_make_request_checks(struct bio *bio) 1855 { :: 1892 /* 1893 * Filter flush bio's early so that make_request based 1894 * drivers without flush support don't have to worry 1895 * about them. 1896 */ 1897 if ((bio->bi_opf & (REQ_PREFLUSH | REQ_FUA)) && 1898 !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { 1899 bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA); 1900 if (!nr_sectors) { 1901 err = 0; 1902 goto end_io; <- this should goto not_supported 1903 } 1904 } :: 1946 not_supported: 1947 err = -EOPNOTSUPP; ------------------------------------------------ Pls ignore this patch. I have submitted [PATCH] btrfs: check if the device is flush capable which will remain unaffected by the above bug/not-a-bug in the blk core code. Thanks, Anand > Otherwise the patch is ok.