From patchwork Thu Jul 3 19:16:20 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 4476691 X-Patchwork-Delegate: snitzer@redhat.com Return-Path: X-Original-To: patchwork-dm-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 665609F36A for ; Thu, 3 Jul 2014 19:20:42 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 371FE20279 for ; Thu, 3 Jul 2014 19:20:41 +0000 (UTC) Received: from mx4-phx2.redhat.com (mx4-phx2.redhat.com [209.132.183.25]) by mail.kernel.org (Postfix) with ESMTP id 08A73203E1 for ; Thu, 3 Jul 2014 19:20:39 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by mx4-phx2.redhat.com (8.13.8/8.13.8) with ESMTP id s63JGM6f026607; Thu, 3 Jul 2014 15:16:22 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id s63JGLbK017128 for ; Thu, 3 Jul 2014 15:16:21 -0400 Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s63JGK8A029801 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 3 Jul 2014 15:16:21 -0400 Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id s63JGKHe003949; Thu, 3 Jul 2014 15:16:20 -0400 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id s63JGKEd003945; Thu, 3 Jul 2014 15:16:20 -0400 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Thu, 3 Jul 2014 15:16:20 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Jens Axboe Message-ID: User-Agent: Alpine 2.02 (LRH 1266 2009-07-14) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-loop: dm-devel@redhat.com Cc: dm-devel@redhat.com, linux-kernel@vger.kernel.org Subject: [dm-devel] [PATCH] blk-lib: fix error reporting X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk Reply-To: device-mapper development List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The function bio_batch_end_io ignores -EOPNOTSUPP. It doesn't matter for discard (the device isn't required to discard anything, so missing the error code and reporting success shouldn't cause any trouble). However, for WRITE SAME command, missing the error code is obviously wrong. It may fool the user into thinking that the data were written while in fact they weren't. Note that in device mapper, devices may be dynamically reconfigured, so a device that supports WRITE SAME may stop supporting it at any time and return -EOPNOTSUPP. Ignoring -EOPNOTSUPP is wrong. This patch changes bio_batch->flags to an error field and stores the last error there - so that the error is reported accurately and it isn't ignored. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org --- block/blk-lib.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel Index: linux-3.16-rc3/block/blk-lib.c =================================================================== --- linux-3.16-rc3.orig/block/blk-lib.c 2014-07-03 18:17:21.000000000 +0200 +++ linux-3.16-rc3/block/blk-lib.c 2014-07-03 18:36:52.000000000 +0200 @@ -11,7 +11,7 @@ struct bio_batch { atomic_t done; - unsigned long flags; + int error; struct completion *wait; }; @@ -19,8 +19,8 @@ static void bio_batch_end_io(struct bio { struct bio_batch *bb = bio->bi_private; - if (err && (err != -EOPNOTSUPP)) - clear_bit(BIO_UPTODATE, &bb->flags); + if (unlikely(err)) + ACCESS_ONCE(bb->error) = err; if (atomic_dec_and_test(&bb->done)) complete(bb->wait); bio_put(bio); @@ -78,7 +78,7 @@ int blkdev_issue_discard(struct block_de } atomic_set(&bb.done, 1); - bb.flags = 1 << BIO_UPTODATE; + bb.error = 0; bb.wait = &wait; blk_start_plug(&plug); @@ -134,8 +134,8 @@ int blkdev_issue_discard(struct block_de if (!atomic_dec_and_test(&bb.done)) wait_for_completion_io(&wait); - if (!test_bit(BIO_UPTODATE, &bb.flags)) - ret = -EIO; + if (likely(!ret)) + ret = bb.error; return ret; } @@ -172,7 +172,7 @@ int blkdev_issue_write_same(struct block return -EOPNOTSUPP; atomic_set(&bb.done, 1); - bb.flags = 1 << BIO_UPTODATE; + bb.error = 0; bb.wait = &wait; while (nr_sects) { @@ -208,8 +208,8 @@ int blkdev_issue_write_same(struct block if (!atomic_dec_and_test(&bb.done)) wait_for_completion_io(&wait); - if (!test_bit(BIO_UPTODATE, &bb.flags)) - ret = -ENOTSUPP; + if (likely(!ret)) + ret = bb.error; return ret; } @@ -236,7 +236,7 @@ static int __blkdev_issue_zeroout(struct DECLARE_COMPLETION_ONSTACK(wait); atomic_set(&bb.done, 1); - bb.flags = 1 << BIO_UPTODATE; + bb.error = 0; bb.wait = &wait; ret = 0; @@ -270,9 +270,8 @@ static int __blkdev_issue_zeroout(struct if (!atomic_dec_and_test(&bb.done)) wait_for_completion_io(&wait); - if (!test_bit(BIO_UPTODATE, &bb.flags)) - /* One of bios in the batch was completed with error.*/ - ret = -EIO; + if (likely(!ret)) + ret = bb.error; return ret; }