From mboxrd@z Thu Jan 1 00:00:00 1970 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 10E46C021AA for ; Wed, 19 Feb 2025 12:36:32 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tkjIh-0003aL-J4; Wed, 19 Feb 2025 07:35:39 -0500 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 1tkhi4-0002PN-Bp for qemu-devel@nongnu.org; Wed, 19 Feb 2025 05:53:44 -0500 Received: from mail-lj1-x22b.google.com ([2a00:1450:4864:20::22b]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1tkhi0-0004rn-Vi for qemu-devel@nongnu.org; Wed, 19 Feb 2025 05:53:44 -0500 Received: by mail-lj1-x22b.google.com with SMTP id 38308e7fff4ca-30761be8fa7so66932361fa.2 for ; Wed, 19 Feb 2025 02:53:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1739962418; x=1740567218; darn=nongnu.org; h=to:subject:message-id:date:from:mime-version:from:to:cc:subject :date:message-id:reply-to; bh=iJ9stCGeL3YQyXHv6c2zusw2mEv+Og/V0/o1mL/JxVg=; b=YhDqyFtKQoLvRiDExQAynNGodxPCsvw9HOzRZf3BaEb5sjDhz4oEyynkUJUr1oWhUL fLPfzMRbmQNytOBN84RUo4yhEp+uBj8dubO8B3IGGgktJFj/39Ru6J04LI8n2zslk/46 frzxIs2eEtclk1fuHDl31OgBmhYBh4CrkTsg1q9sKTKS/HXy/GKSOWq+nuxV2RZ3d1s4 p4CxTV9DemooKxfF5aR/S3DCcGTf8oNtPr1VFasySF69ZnVKmXlvVw3R3p8wc9ZntVbv IQ9mnk7597aBoXGzExJf8vGTf/tsJLneBi0MoO1plIOuaQl/H3u5AtRxYQxHj4qiMX7B twHw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739962418; x=1740567218; h=to:subject:message-id:date:from:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=iJ9stCGeL3YQyXHv6c2zusw2mEv+Og/V0/o1mL/JxVg=; b=wOMp10G1l6oeAo2AY8VyprXMGlCNj1A5f4wD/EM29xPwsEsl/DrVsnuHDsmlRX0pK0 dmMjtE/gy9Uz2PTpzp0IlN8U6FOQocq4l6IytDKSobVvto0LSps72RO/L54d960TDYX7 F8O5A0WRDjV2YbJGsIKpRN1HUWA17PmljrIXriqC4k4EbdbCFwjeUpWqPnCv8V0a91tp 0oU8y6D+CX0NTGqDrDNBkycdiUCexCbQ26vKnb8Kfz+8b09QcJTRcoZznHBxjpjlztsC uQP+CJv9AAOLXnPhrS1ypn8hVThs7/LaQh4qOgQBbjpB1f+opWyN5RJX/3T041kuHbkL nkkQ== X-Gm-Message-State: AOJu0Yx57wy10JX9VrbJax+ZAr9wX6wQEUTdk1U7W0BP72XgIyG97W2r ohh4D96KJXfBQnrl5ZIMtpD+p/913RwY97nfePj6VLtARCXo0B9hg6tS+VRobvIQFE89rJTnQ5y cPy+OlgC8pWuVFmCv6gLJXgivBeLCN3rf X-Gm-Gg: ASbGncvQhxkIowEK1qKGu22DJLz533fRtaNf3U+AgT6JfXXoZ/06vliGXpFHKlsLZPM 1oX6c9To1hl+YNyXKDO0RgNUFuGWA+38zXOSz2rYH1SXI8/xig5Iv6o8Xx3GnCksh3m2VG8M= X-Google-Smtp-Source: AGHT+IFpAijT5/hhfxunQ1pw1IJzBl+1P3Lp7UZgWG38TE8PPrz8jr02u8u0AiiB21yhr+S/gDNi0E9te0raQRh5UzY= X-Received: by 2002:a2e:8050:0:b0:302:2598:dec2 with SMTP id 38308e7fff4ca-30a44dc4a86mr9012121fa.14.1739962417535; Wed, 19 Feb 2025 02:53:37 -0800 (PST) MIME-Version: 1.0 From: prashant patil Date: Wed, 19 Feb 2025 16:23:26 +0530 X-Gm-Features: AWEUYZljgtq6oXFI5x0fFvnjpUt0f5ewCuLs30s6Bs5yyOLnODga6i_IpUFsrVg Message-ID: Subject: Query on the dirty bitmap To: qemu-devel@nongnu.org Content-Type: multipart/alternative; boundary="000000000000d1e3ce062e7c918d" Received-SPF: pass client-ip=2a00:1450:4864:20::22b; envelope-from=pmgpatil@gmail.com; helo=mail-lj1-x22b.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Wed, 19 Feb 2025 07:35:38 -0500 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --000000000000d1e3ce062e7c918d Content-Type: text/plain; charset="UTF-8" Hello All, Hope this email finds you well. I have been trying with qemu for a while now, and have come across a problem specific to dirty bitmaps. I have enabled bitmap on the qcow2 disk image using 'qemu-img bitmap' command, exposed the bitmap over a unix socket using 'qemu-nbd' command. Now when I try to read the bitmap using 'qemu-img map' command with 'x-dirty-bitmap=qemu:dirty-bitmap:{bitmap}' option, I get one single extent which shows that the entire disk is dirty. Note that the disk size is 5 GB, and has only a few MB of data in it, and had added very small data after the bitmap was enabled. Bitmap output has been pasted below. [{ "start": 0, "length": 5368709120, "depth": 0, "present": true, "zero": false, "data": true, "compressed": false, "offset": 0}] Can someone please help me understand why the bitmap content shows the entire disk as dirty? Regards Prashant --000000000000d1e3ce062e7c918d Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hello All,
Hope this email finds you well.
<= br>
I have been trying with qemu for a while now, and have come a= cross a problem specific to dirty bitmaps. I have enabled bitmap on the qco= w2 disk image using 'qemu-img bitmap' command, exposed the bitmap o= ver a unix socket using 'qemu-nbd' command. Now when I try to read = the bitmap using 'qemu-img map' command with 'x-dirty-bitmap=3D= qemu:dirty-bitmap:{bitmap}' option, I get one single extent which shows= that the entire disk is dirty. Note that the disk size is 5 GB, and has on= ly a few MB of data in it, and had added very small data after the bitmap w= as enabled. Bitmap output has been pasted below.

[= { "start": 0, "length": 5368709120, "depth": = 0, "present": true, "zero": false, "data": tr= ue, "compressed": false, "offset": 0}]

Can someone please help me understand why the bitmap content shows= the entire disk as dirty?

Regards
Prash= ant
--000000000000d1e3ce062e7c918d--