From patchwork Tue Jul 30 17:25:01 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 11066355 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4E2A814DB for ; Tue, 30 Jul 2019 17:35:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 34FE8205AD for ; Tue, 30 Jul 2019 17:35:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 29491286F1; Tue, 30 Jul 2019 17:35:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 9CAE2205AD for ; Tue, 30 Jul 2019 17:35:15 +0000 (UTC) Received: from localhost ([::1]:35072 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsW1q-0003Ao-VU for patchwork-qemu-devel@patchwork.kernel.org; Tue, 30 Jul 2019 13:35:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33590) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsVsW-000705-Ae for qemu-devel@nongnu.org; Tue, 30 Jul 2019 13:25:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hsVsU-0002is-EA for qemu-devel@nongnu.org; Tue, 30 Jul 2019 13:25:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:19689) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hsVsO-0002bj-VL; Tue, 30 Jul 2019 13:25:29 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9FE3A3087958; Tue, 30 Jul 2019 17:25:27 +0000 (UTC) Received: from localhost (ovpn-116-164.ams2.redhat.com [10.36.116.164]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EE90F5D9C5; Tue, 30 Jul 2019 17:25:26 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Tue, 30 Jul 2019 19:25:01 +0200 Message-Id: <20190730172508.19911-7-mreitz@redhat.com> In-Reply-To: <20190730172508.19911-1-mreitz@redhat.com> References: <20190730172508.19911-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Tue, 30 Jul 2019 17:25:27 +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-4.2 06/13] qcow2: Separate qcow2_check_read_snapshot_table() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Reading the snapshot table can fail. That is a problem when we want to repair the image. Therefore, stop reading the snapshot table in qcow2_do_open() in check mode. Instead, add a new function qcow2_check_read_snapshot_table() that reads the snapshot table at a later point. In the future, we want to handle errors here and fix them. Signed-off-by: Max Reitz Reviewed-by: Eric Blake --- block/qcow2.h | 4 +++ block/qcow2-snapshot.c | 58 ++++++++++++++++++++++++++++++++ block/qcow2.c | 76 ++++++++++++++++++++++++++++++++---------- 3 files changed, 120 insertions(+), 18 deletions(-) diff --git a/block/qcow2.h b/block/qcow2.h index 77586d81b9..50c7eefb5b 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -712,6 +712,10 @@ void qcow2_free_snapshots(BlockDriverState *bs); int qcow2_read_snapshots(BlockDriverState *bs, Error **errp); int qcow2_write_snapshots(BlockDriverState *bs); +int coroutine_fn qcow2_check_read_snapshot_table(BlockDriverState *bs, + BdrvCheckResult *result, + BdrvCheckMode fix); + /* qcow2-cache.c functions */ Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables, unsigned table_size); diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 3d097b92d7..cbc6d699b6 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -321,6 +321,64 @@ fail: return ret; } +int coroutine_fn qcow2_check_read_snapshot_table(BlockDriverState *bs, + BdrvCheckResult *result, + BdrvCheckMode fix) +{ + BDRVQcow2State *s = bs->opaque; + Error *local_err = NULL; + int ret; + struct { + uint32_t nb_snapshots; + uint64_t snapshots_offset; + } QEMU_PACKED snapshot_table_pointer; + + /* qcow2_do_open() discards this information in check mode */ + ret = bdrv_pread(bs->file, 60, &snapshot_table_pointer, + sizeof(snapshot_table_pointer)); + if (ret < 0) { + result->check_errors++; + fprintf(stderr, "ERROR failed to read the snapshot table pointer from " + "the image header: %s\n", strerror(-ret)); + return ret; + } + + s->snapshots_offset = be64_to_cpu(snapshot_table_pointer.snapshots_offset); + s->nb_snapshots = be32_to_cpu(snapshot_table_pointer.nb_snapshots); + + ret = qcow2_validate_table(bs, s->snapshots_offset, s->nb_snapshots, + sizeof(QCowSnapshotHeader), + sizeof(QCowSnapshotHeader) * QCOW_MAX_SNAPSHOTS, + "snapshot table", &local_err); + if (ret < 0) { + result->check_errors++; + error_reportf_err(local_err, "ERROR "); + + /* We did not read the snapshot table, so invalidate this information */ + s->snapshots_offset = 0; + s->nb_snapshots = 0; + + return ret; + } + + qemu_co_mutex_unlock(&s->lock); + ret = qcow2_read_snapshots(bs, &local_err); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + result->check_errors++; + error_reportf_err(local_err, + "ERROR failed to read the snapshot table: "); + + /* We did not read the snapshot table, so invalidate this information */ + s->snapshots_offset = 0; + s->nb_snapshots = 0; + + return ret; + } + + return 0; +} + static void find_new_snapshot_id(BlockDriverState *bs, char *id_str, int id_str_size) { diff --git a/block/qcow2.c b/block/qcow2.c index 75d41683a1..2983a7795a 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -567,11 +567,40 @@ int qcow2_mark_consistent(BlockDriverState *bs) return 0; } +static void qcow2_add_check_result(BdrvCheckResult *out, + const BdrvCheckResult *src, + bool set_allocation_info) +{ + out->corruptions += src->corruptions; + out->leaks += src->leaks; + out->check_errors += src->check_errors; + out->corruptions_fixed += src->corruptions_fixed; + out->leaks_fixed += src->leaks_fixed; + + if (set_allocation_info) { + out->image_end_offset = src->image_end_offset; + out->bfi = src->bfi; + } +} + static int coroutine_fn qcow2_co_check_locked(BlockDriverState *bs, BdrvCheckResult *result, BdrvCheckMode fix) { - int ret = qcow2_check_refcounts(bs, result, fix); + BdrvCheckResult snapshot_res = {}; + BdrvCheckResult refcount_res = {}; + int ret; + + memset(result, 0, sizeof(*result)); + + ret = qcow2_check_read_snapshot_table(bs, &snapshot_res, fix); + qcow2_add_check_result(result, &snapshot_res, false); + if (ret < 0) { + return ret; + } + + ret = qcow2_check_refcounts(bs, &refcount_res, fix); + qcow2_add_check_result(result, &refcount_res, true); if (ret < 0) { return ret; } @@ -1403,17 +1432,22 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, goto fail; } - /* The total size in bytes of the snapshot table is checked in - * qcow2_read_snapshots() because the size of each snapshot is - * variable and we don't know it yet. - * Here we only check the offset and number of snapshots. */ - ret = qcow2_validate_table(bs, header.snapshots_offset, - header.nb_snapshots, - sizeof(QCowSnapshotHeader), - sizeof(QCowSnapshotHeader) * QCOW_MAX_SNAPSHOTS, - "Snapshot table", errp); - if (ret < 0) { - goto fail; + if (!(flags & BDRV_O_CHECK)) { + /* + * The total size in bytes of the snapshot table is checked in + * qcow2_read_snapshots() because the size of each snapshot is + * variable and we don't know it yet. + * Here we only check the offset and number of snapshots. + */ + ret = qcow2_validate_table(bs, header.snapshots_offset, + header.nb_snapshots, + sizeof(QCowSnapshotHeader), + sizeof(QCowSnapshotHeader) * + QCOW_MAX_SNAPSHOTS, + "Snapshot table", errp); + if (ret < 0) { + goto fail; + } } /* read the level 1 table */ @@ -1573,13 +1607,19 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, s->image_backing_file = g_strdup(bs->auto_backing_file); } - /* Internal snapshots */ - s->snapshots_offset = header.snapshots_offset; - s->nb_snapshots = header.nb_snapshots; + /* + * Internal snapshots; skip reading them in check mode, because + * we do not need them then, and we do not want to abort because + * of a broken table. + */ + if (!(flags & BDRV_O_CHECK)) { + s->snapshots_offset = header.snapshots_offset; + s->nb_snapshots = header.nb_snapshots; - ret = qcow2_read_snapshots(bs, errp); - if (ret < 0) { - goto fail; + ret = qcow2_read_snapshots(bs, errp); + if (ret < 0) { + goto fail; + } } /* Clear unknown autoclear feature bits */