From patchwork Thu May 25 18:02:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Drobyshev X-Patchwork-Id: 13255544 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E5254C7EE2F for ; Thu, 25 May 2023 18:02:56 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1q2FIL-0003dy-LB; Thu, 25 May 2023 14:02:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q2FI3-0003bF-Ic; Thu, 25 May 2023 14:02:19 -0400 Received: from relay.virtuozzo.com ([130.117.225.111]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q2FI1-0003J6-OK; Thu, 25 May 2023 14:02:18 -0400 Received: from dev005.ch-qa.vzint.dev ([172.29.1.10]) by relay.virtuozzo.com with esmtp (Exim 4.96) (envelope-from ) id 1q2FGW-002Ggr-1o; Thu, 25 May 2023 20:02:12 +0200 To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, kwolf@redhat.com, shmuel.eiderman@oracle.com, andrey.drobyshev@virtuozzo.com, den@virtuozzo.com Subject: [PATCH v2 1/2] qemu-img: rebase: stop when reaching EOF of old backing file Date: Thu, 25 May 2023 21:02:12 +0300 Message-Id: <20230525180213.902012-2-andrey.drobyshev@virtuozzo.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230525180213.902012-1-andrey.drobyshev@virtuozzo.com> References: <20230525180213.902012-1-andrey.drobyshev@virtuozzo.com> MIME-Version: 1.0 Received-SPF: pass client-ip=130.117.225.111; envelope-from=andrey.drobyshev@virtuozzo.com; helo=relay.virtuozzo.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Andrey Drobyshev X-Patchwork-Original-From: Andrey Drobyshev via From: Andrey Drobyshev Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org In case when we're rebasing within one backing chain, and when target image is larger than old backing file, bdrv_is_allocated_above() ends up setting *pnum = 0. As a result, target offset isn't getting incremented, and we get stuck in an infinite for loop. Let's detect this case and proceed further down the loop body, as the offsets beyond the old backing size need to be explicitly zeroed. Signed-off-by: Andrey Drobyshev --- qemu-img.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/qemu-img.c b/qemu-img.c index 27f48051b0..78433f3746 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3801,6 +3801,8 @@ static int img_rebase(int argc, char **argv) } if (prefix_chain_bs) { + uint64_t bytes = n; + /* * If cluster wasn't changed since prefix_chain, we don't need * to take action @@ -3813,9 +3815,18 @@ static int img_rebase(int argc, char **argv) strerror(-ret)); goto out; } - if (!ret) { + if (!ret && n) { continue; } + if (!n) { + /* + * If we've reached EOF of the old backing, it means that + * offsets beyond the old backing size were read as zeroes. + * Now we will need to explicitly zero the cluster in + * order to preserve that state after the rebase. + */ + n = bytes; + } } /* From patchwork Thu May 25 18:02:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Drobyshev X-Patchwork-Id: 13255543 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 32C7BC77B7E for ; Thu, 25 May 2023 18:02:55 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1q2FIM-0003hN-9x; Thu, 25 May 2023 14:02:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q2FI4-0003bW-NY; Thu, 25 May 2023 14:02:20 -0400 Received: from relay.virtuozzo.com ([130.117.225.111]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q2FI1-0003J7-QG; Thu, 25 May 2023 14:02:20 -0400 Received: from dev005.ch-qa.vzint.dev ([172.29.1.10]) by relay.virtuozzo.com with esmtp (Exim 4.96) (envelope-from ) id 1q2FGW-002Ggr-1y; Thu, 25 May 2023 20:02:12 +0200 To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, kwolf@redhat.com, shmuel.eiderman@oracle.com, andrey.drobyshev@virtuozzo.com, den@virtuozzo.com Subject: [PATCH v2 2/2] qemu-iotests: 024: add rebasing test case for overlay_size > backing_size Date: Thu, 25 May 2023 21:02:13 +0300 Message-Id: <20230525180213.902012-3-andrey.drobyshev@virtuozzo.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230525180213.902012-1-andrey.drobyshev@virtuozzo.com> References: <20230525180213.902012-1-andrey.drobyshev@virtuozzo.com> MIME-Version: 1.0 Received-SPF: pass client-ip=130.117.225.111; envelope-from=andrey.drobyshev@virtuozzo.com; helo=relay.virtuozzo.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Andrey Drobyshev X-Patchwork-Original-From: Andrey Drobyshev via From: Andrey Drobyshev Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Before previous commit, rebase was getting infitely stuck in case of rebasing within the same backing chain and when overlay_size > backing_size. Let's add this case to the rebasing test 024 to make sure it doesn't break again. Signed-off-by: Andrey Drobyshev Reviewed-by: Denis V. Lunev --- tests/qemu-iotests/024 | 57 ++++++++++++++++++++++++++++++++++++++ tests/qemu-iotests/024.out | 30 ++++++++++++++++++++ 2 files changed, 87 insertions(+) diff --git a/tests/qemu-iotests/024 b/tests/qemu-iotests/024 index 25a564a150..98a7c8fd65 100755 --- a/tests/qemu-iotests/024 +++ b/tests/qemu-iotests/024 @@ -199,6 +199,63 @@ echo # $BASE_OLD and $BASE_NEW) $QEMU_IMG map "$OVERLAY" | _filter_qemu_img_map +# Check that rebase within the chain is working when +# overlay_size > old_backing_size +# +# base_new <-- base_old <-- overlay +# +# Backing (new): 11 11 11 11 11 +# Backing (old): 22 22 22 22 +# Overlay: -- -- -- -- -- +# +# As a result, overlay should contain data identical to base_old, with the +# last cluster remaining unallocated. + +echo +echo "=== Test rebase within one backing chain ===" +echo + +echo "Creating backing chain" +echo + +TEST_IMG=$BASE_NEW _make_test_img $(( CLUSTER_SIZE * 5 )) +TEST_IMG=$BASE_OLD _make_test_img -b "$BASE_NEW" -F $IMGFMT \ + $(( CLUSTER_SIZE * 4 )) +TEST_IMG=$OVERLAY _make_test_img -b "$BASE_OLD" -F $IMGFMT \ + $(( CLUSTER_SIZE * 5 )) + +echo +echo "Fill backing files with data" +echo + +$QEMU_IO "$BASE_NEW" -c "write -P 0x11 0 $(( CLUSTER_SIZE * 5 ))" \ + | _filter_qemu_io +$QEMU_IO "$BASE_OLD" -c "write -P 0x22 0 $(( CLUSTER_SIZE * 4 ))" \ + | _filter_qemu_io + +echo +echo "Check the last cluster is zeroed in overlay before the rebase" +echo +$QEMU_IO "$OVERLAY" -c "read -P 0x00 $(( CLUSTER_SIZE * 4 )) $CLUSTER_SIZE" \ + | _filter_qemu_io + +echo +echo "Rebase onto another image in the same chain" +echo + +$QEMU_IMG rebase -b "$BASE_NEW" -F $IMGFMT "$OVERLAY" + +echo "Verify that data is read the same before and after rebase" +echo + +# Verify the first 4 clusters are still read the same as in the old base +$QEMU_IO "$OVERLAY" -c "read -P 0x22 0 $(( CLUSTER_SIZE * 4 ))" \ + | _filter_qemu_io +# Verify the last cluster still reads as zeroes +$QEMU_IO "$OVERLAY" -c "read -P 0x00 $(( CLUSTER_SIZE * 4 )) $CLUSTER_SIZE" \ + | _filter_qemu_io + +echo # success, all done echo "*** done" diff --git a/tests/qemu-iotests/024.out b/tests/qemu-iotests/024.out index 973a5a3711..245fe8b1d1 100644 --- a/tests/qemu-iotests/024.out +++ b/tests/qemu-iotests/024.out @@ -171,4 +171,34 @@ read 65536/65536 bytes at offset 196608 Offset Length File 0 0x30000 TEST_DIR/subdir/t.IMGFMT 0x30000 0x10000 TEST_DIR/subdir/t.IMGFMT.base_new + +=== Test rebase within one backing chain === + +Creating backing chain + +Formatting 'TEST_DIR/subdir/t.IMGFMT.base_new', fmt=IMGFMT size=327680 +Formatting 'TEST_DIR/subdir/t.IMGFMT.base_old', fmt=IMGFMT size=262144 backing_file=TEST_DIR/subdir/t.IMGFMT.base_new backing_fmt=IMGFMT +Formatting 'TEST_DIR/subdir/t.IMGFMT', fmt=IMGFMT size=327680 backing_file=TEST_DIR/subdir/t.IMGFMT.base_old backing_fmt=IMGFMT + +Fill backing files with data + +wrote 327680/327680 bytes at offset 0 +320 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +wrote 262144/262144 bytes at offset 0 +256 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) + +Check the last cluster is zeroed in overlay before the rebase + +read 65536/65536 bytes at offset 262144 +64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) + +Rebase onto another image in the same chain + +Verify that data is read the same before and after rebase + +read 262144/262144 bytes at offset 0 +256 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +read 65536/65536 bytes at offset 262144 +64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) + *** done