From patchwork Tue Mar 26 18:40:43 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Blake X-Patchwork-Id: 1065958 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 44TKjx56rHz9sRY for ; Wed, 27 Mar 2019 05:42:13 +1100 (AEDT) Received: from localhost ([127.0.0.1]:36396 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h8r1X-0007oQ-Lr for incoming@patchwork.ozlabs.org; Tue, 26 Mar 2019 14:42:11 -0400 Received: from eggs.gnu.org ([209.51.188.92]:59017) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h8r0f-0007bV-Sa for qemu-devel@nongnu.org; Tue, 26 Mar 2019 14:41:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h8r0b-0002xr-6c for qemu-devel@nongnu.org; Tue, 26 Mar 2019 14:41:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55754) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1h8r0S-0002ga-ID; Tue, 26 Mar 2019 14:41:05 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 123F030832E8; Tue, 26 Mar 2019 18:40:48 +0000 (UTC) Received: from blue.redhat.com (ovpn-116-59.phx2.redhat.com [10.3.116.59]) by smtp.corp.redhat.com (Postfix) with ESMTP id 577E35799; Tue, 26 Mar 2019 18:40:47 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Date: Tue, 26 Mar 2019 13:40:43 -0500 Message-Id: <20190326184043.7544-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Tue, 26 Mar 2019 18:40:48 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH for-4.0] qemu-img: Gracefully shutdown when map can't finish X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , "open list:Block layer core" , Max Reitz Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Trying 'qemu-img map -f raw nbd://localhost:10809' causes the NBD server to output a scary message: qemu-nbd: Disconnect client, due to: Failed to read request: Unexpected end-of-file before all bytes were read This is because the NBD client, being remote, has no way to expose a human-readable map (the --output=json data is fine, however). But because we exit(1) right after the message, causing the client to bypass all block cleanup, the server sees the abrupt exit and warns, whereas it would be silent had the client had a chance to send NBD_CMD_DISC. Other protocols may have similar cleanup issues, where failure to blk_unref() could cause unintended effects. Signed-off-by: Eric Blake Reviewed-by: John Snow Reviewed-by: Kevin Wolf --- Since I found this while testing NBD, I'm happy to include it through my tree. qemu-img.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index 12f071a1ca2..55c599841a1 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -2736,14 +2736,14 @@ static int img_info(int argc, char **argv) return 0; } -static void dump_map_entry(OutputFormat output_format, MapEntry *e, - MapEntry *next) +static int dump_map_entry(OutputFormat output_format, MapEntry *e, + MapEntry *next) { switch (output_format) { case OFORMAT_HUMAN: if (e->data && !e->has_offset) { error_report("File contains external, encrypted or compressed clusters."); - exit(1); + return -1; } if (e->data && !e->zero) { printf("%#-16"PRIx64"%#-16"PRIx64"%#-16"PRIx64"%s\n", @@ -2776,6 +2776,7 @@ static void dump_map_entry(OutputFormat output_format, MapEntry *e, } break; } + return 0; } static int get_block_status(BlockDriverState *bs, int64_t offset, @@ -2968,12 +2969,15 @@ static int img_map(int argc, char **argv) } if (curr.length > 0) { - dump_map_entry(output_format, &curr, &next); + ret = dump_map_entry(output_format, &curr, &next); + if (ret < 0) { + goto out; + } } curr = next; } - dump_map_entry(output_format, &curr, NULL); + ret = dump_map_entry(output_format, &curr, NULL); out: blk_unref(blk);